{"id":103210,"date":"2026-09-10T02:57:04","date_gmt":"2026-09-09T18:57:04","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/103210.html"},"modified":"2026-09-10T02:57:04","modified_gmt":"2026-09-09T18:57:04","slug":"%e3%80%90%e5%a4%9a%e7%ba%bf%e7%a8%8b%e3%80%91-concurrenthashmap-%e6%ba%90%e7%a0%81%e8%a7%a3%e6%9e%90","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/103210.html","title":{"rendered":"\u3010\u591a\u7ebf\u7a0b\u3011---ConcurrentHashMap \u6e90\u7801\u89e3\u6790"},"content":{"rendered":"<p>\u57fa\u4e8e&#xff1a;OpenJDK JDK 8u \u7684 java.util.concurrent.ConcurrentHashMap&#xff08;\u5bf9\u7167 JDK 7 \u5206\u6bb5\u9501\u5b9e\u73b0\u4e0e JDK 9&#043; \u6f14\u8fdb&#xff09;<\/p>\n<p>\u672c\u6587\u4ee5\u6e90\u7801\u89e3\u6790\u4e3a\u4e3b\u7ebf&#xff0c;\u9010\u6bb5\u62c6\u89e3 JDK 8 \u7248 ConcurrentHashMap \u7684\u6838\u5fc3\u5b9e\u73b0&#xff1a;\u5b57\u6bb5\u4e0e sizeCtl \u8bed\u4e49\u3001putVal \u5168\u94fe\u8def\u3001\u591a\u7ebf\u7a0b\u534f\u4f5c\u6269\u5bb9\u3001\u65e0\u9501\u8bfb\u3001\u57fa\u4e8e CounterCell \u7684\u8ba1\u6570\u3001\u7ea2\u9ed1\u6811\u5316\u4e0e TreeBin&#xff0c;\u914d\u5408\u6570\u636e\u5e03\u5c40\u603b\u56fe\u3001\u7c7b\u5173\u7cfb\u56fe\u3001\u53ef\u8fd0\u884c\u793a\u4f8b\u4e0e\u9762\u8bd5 FAQ\u3002\u89e3\u51b3\u300c\u6e90\u7801\u8bfb\u4e86\u8bb0\u4e0d\u4f4f\u3001\u9762\u8bd5\u8bb2\u4e0d\u6e05 put \u4e4b\u540e\u53d1\u751f\u4e86\u4ec0\u4e48\u300d\u7684\u95ee\u9898\u3002<\/p>\n<hr \/>\n<h3>\u76ee\u5f55<\/h3>\n<li>\u5b9a\u4f4d\u4e0e\u5386\u53f2\u6f14\u8fdb\n<ul>\n<li>1.1 \u4e00\u53e5\u8bdd\u5b9a\u4f4d<\/li>\n<li>1.2 \u7ebf\u7a0b\u5b89\u5168\u5bb9\u5668\u5b9a\u4f4d\u8868<\/li>\n<li>1.3 \u4ece JDK 7 \u5230 JDK 8 \u7684\u6f14\u8fdb<\/li>\n<\/ul>\n<\/li>\n<li>\u6574\u4f53\u8bbe\u8ba1\u603b\u89c8\n<ul>\n<li>2.1 \u6570\u636e\u5e03\u5c40<\/li>\n<li>2.2 put \u4e3b\u6d41\u7a0b\u603b\u89c8<\/li>\n<li>2.3 \u6838\u5fc3\u5b57\u6bb5\u8868<\/li>\n<li>2.4 sizeCtl \u7684\u8bed\u4e49<\/li>\n<\/ul>\n<\/li>\n<li>\u5165\u53e3\u4e0e\u6784\u9020\n<ul>\n<li>3.1 \u7c7b\u58f0\u660e\u4e0e\u91cd\u8981\u5e38\u91cf<\/li>\n<li>3.2 \u6784\u9020\u5668\u4e0e\u61d2\u521d\u59cb\u5316<\/li>\n<li>3.3 Node \u5185\u90e8\u7c7b\u4f53\u7cfb<\/li>\n<\/ul>\n<\/li>\n<li>putVal \u5206\u6b65\u8be6\u89e3\n<ul>\n<li>4.1 \u5b9a\u4f4d\u4e0e\u7a7a\u6876 CAS<\/li>\n<li>4.2 MOVED \u4e0e\u534f\u52a9\u6269\u5bb9<\/li>\n<li>4.3 \u6876\u5934\u52a0\u9501\u5199\u5165<\/li>\n<li>4.4 \u6811\u5316\u89e6\u53d1<\/li>\n<li>4.5 \u8ba1\u6570\u4e0e\u9608\u503c\u68c0\u67e5<\/li>\n<li>4.6 put \u5168\u6d41\u7a0b\u51b3\u7b56\u56fe<\/li>\n<\/ul>\n<\/li>\n<li>\u6269\u5bb9\u673a\u5236 transfer\n<ul>\n<li>5.1 \u6269\u5bb9\u89e6\u53d1\u70b9<\/li>\n<li>5.2 \u591a\u7ebf\u7a0b\u5206\u5de5\u4e0e\u533a\u95f4\u9886\u53d6<\/li>\n<li>5.3 \u6876\u8fc1\u79fb\u4e0e\u9ad8\u4f4e\u4f4d\u62c6\u5206<\/li>\n<li>5.4 ForwardingNode \u4e0e\u65e0\u9501\u8bfb<\/li>\n<\/ul>\n<\/li>\n<li>\u8ba1\u6570\u673a\u5236\n<ul>\n<li>6.1 CounterCell \u4e0e\u4f2a\u5171\u4eab<\/li>\n<li>6.2 addCount \u4e0e fullAddCount<\/li>\n<li>6.3 size \u4e0e mappingCount<\/li>\n<\/ul>\n<\/li>\n<li>\u8bfb\u64cd\u4f5c\u4e0e\u904d\u5386\n<ul>\n<li>7.1 get \u4e3a\u4ec0\u4e48\u53ef\u4ee5\u65e0\u9501<\/li>\n<li>7.2 remove \u4e0e replace<\/li>\n<li>7.3 \u5f31\u4e00\u81f4\u6027\u8fed\u4ee3\u5668<\/li>\n<li>7.4 \u590d\u5408\u64cd\u4f5c compute \u7cfb\u5217<\/li>\n<\/ul>\n<\/li>\n<li>\u6811\u5316\u4e0e TreeBin\n<ul>\n<li>8.1 8 \u4e0e 6 \u4e24\u4e2a\u9608\u503c<\/li>\n<li>8.2 TreeBin \u7684\u8bfb\u5199\u9501\u601d\u8def<\/li>\n<li>8.3 \u6811\u4e0e\u94fe\u8868\u7684\u53cc\u5411\u8f6c\u6362<\/li>\n<\/ul>\n<\/li>\n<li>\u5173\u952e\u7c7b\u5173\u7cfb\u56fe<\/li>\n<li>\u53ef\u8fd0\u884c\u793a\u4f8b\n<ul>\n<li>10.1 \u5e76\u53d1\u8bfb\u5199\u4e0e\u904d\u5386 demo<\/li>\n<li>10.2 \u7b80\u6613\u7f13\u5b58 demo<\/li>\n<\/ul>\n<\/li>\n<li>\u6a2a\u5411\u5bf9\u6bd4\u603b\u8868<\/li>\n<li>FAQ \u4e0e\u6269\u5c55\u70b9<\/li>\n<li>\u53c2\u8003\u8d44\u6599\u4e0e\u5ef6\u4f38<\/li>\n<hr \/>\n<h3>1. \u5b9a\u4f4d\u4e0e\u5386\u53f2\u6f14\u8fdb<\/h3>\n<h4>1.1 \u4e00\u53e5\u8bdd\u5b9a\u4f4d<\/h4>\n<p>\u5173\u952e\u8ba4\u77e5&#xff1a;ConcurrentHashMap \u662f JUC \u91cc\u300c\u8bfb\u591a\u5199\u5c11 &#043; \u9ad8\u5e76\u53d1\u5199\u300d\u573a\u666f\u7684\u7ebf\u7a0b\u5b89\u5168 HashMap&#xff0c;JDK 8 \u7248\u672c\u4ee5 CAS &#043; \u6876\u5934 synchronized &#043; \u7ea2\u9ed1\u6811 \u4e3a\u6838\u5fc3&#xff1a;\u628a\u9501\u7c92\u5ea6\u7ec6\u5316\u5230\u6bcf\u4e2a\u54c8\u5e0c\u6876&#xff0c;\u65e0\u7ade\u4e89\u5199\u5165\u53ea\u82b1\u4e00\u6b21 CAS&#xff0c;\u8bfb\u64cd\u4f5c\u5b8c\u5168\u65e0\u9501&#xff0c;\u6269\u5bb9\u652f\u6301\u591a\u7ebf\u7a0b\u534f\u4f5c\u2014\u2014\u5728\u4fdd\u8bc1\u7ebf\u7a0b\u5b89\u5168\u7684\u540c\u65f6&#xff0c;\u628a\u5e76\u53d1\u5ea6\u4ece JDK 7 \u7684\u300c16 \u4e2a\u5206\u6bb5\u300d\u63d0\u5347\u5230\u300c\u6876\u4e2a\u6570\u300d\u7ea7\u522b\u3002<\/p>\n<h4>1.2 \u7ebf\u7a0b\u5b89\u5168\u5bb9\u5668\u5b9a\u4f4d\u8868<\/h4>\n<table>\n<tr>\u5bb9\u5668\u7ebf\u7a0b\u5b89\u5168\u65b9\u5f0f\u9501\u7c92\u5ea6\u8bfb\u6027\u80fd\u5199\u6027\u80fd&#xff08;\u7ade\u4e89&#xff09;\u9002\u7528\u5224\u65ad<\/tr>\n<tbody>\n<tr>\n<td>Hashtable<\/td>\n<td>\u5168\u8868\u4e00\u628a\u9501&#xff08;synchronized \u65b9\u6cd5&#xff09;<\/td>\n<td>\u6574\u4e2a\u8868<\/td>\n<td>\u9501\u5185\u8bfb<\/td>\n<td>\u5f88\u5dee<\/td>\n<td>\u5386\u53f2\u9057\u7559&#xff0c;\u52ff\u7528<\/td>\n<\/tr>\n<tr>\n<td>Collections.synchronizedMap(map)<\/td>\n<td>\u5305\u88c5\u5668\u9501&#xff08;\u9ed8\u8ba4\u9501\u6574\u4e2a map \u5bf9\u8c61&#xff09;<\/td>\n<td>\u6574\u4e2a\u8868<\/td>\n<td>\u9501\u5185\u8bfb<\/td>\n<td>\u5f88\u5dee<\/td>\n<td>\u4ec5\u5c0f\u89c4\u6a21\/\u515c\u5e95\u573a\u666f<\/td>\n<\/tr>\n<tr>\n<td>ConcurrentHashMap&#xff08;JDK 8&#043;&#xff09;<\/td>\n<td>CAS &#043; \u6876\u5934\u9501 &#043; volatile<\/td>\n<td>\u5355\u4e2a\u6876<\/td>\n<td>\u65e0\u9501<\/td>\n<td>\u597d&#xff08;\u5206\u644a\u5230\u6876&#xff09;<\/td>\n<td>\u9ed8\u8ba4\u5e76\u53d1\u9996\u9009<\/td>\n<\/tr>\n<tr>\n<td>HashMap<\/td>\n<td>\u65e0&#xff08;\u4f9d\u8d56\u5916\u90e8\u540c\u6b65&#xff09;<\/td>\n<td>\u2014<\/td>\n<td>\u65e0\u9501\u6700\u5feb<\/td>\n<td>\u65e0\u9501\u6700\u5feb<\/td>\n<td>\u7ebf\u7a0b\u79c1\u6709 \/ \u5916\u90e8\u5df2\u52a0\u9501<\/td>\n<\/tr>\n<tr>\n<td>ConcurrentSkipListMap<\/td>\n<td>CAS &#043; \u8df3\u8868<\/td>\n<td>\u8282\u70b9\u7ea7<\/td>\n<td>\u65e0\u9501<\/td>\n<td>\u597d<\/td>\n<td>\u9700\u8981\u6709\u5e8f\u7684\u5e76\u53d1 Map<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4e00\u53e5\u8bdd\u6982\u62ec&#xff1a;\u51e1\u662f\u300c\u4e00\u4e2a HashMap \u88ab\u591a\u4e2a\u7ebf\u7a0b\u5171\u4eab\u4e14\u9700\u8981\u589e\u5220\u300d&#xff0c;\u9ed8\u8ba4\u7b54\u6848\u5c31\u662f ConcurrentHashMap&#xff1b;Hashtable \u4e0e synchronizedMap \u7684\u5168\u5c40\u9501\u4f1a\u8ba9\u6240\u6709\u64cd\u4f5c\u4e32\u884c\u5316&#xff0c;\u5199\u5165\u4e00\u591a\u5c31\u9000\u5316\u3002<\/p>\n<h4>1.3 \u4ece JDK 7 \u5230 JDK 8 \u7684\u6f14\u8fdb<\/h4>\n<table>\n<tr>\u7ef4\u5ea6JDK 7 ConcurrentHashMapJDK 8 ConcurrentHashMap<\/tr>\n<tbody>\n<tr>\n<td>\u6570\u636e\u7ed3\u6784<\/td>\n<td>Segment \u6570\u7ec4&#xff08;\u5206\u6bb5\u9501&#xff09;&#043; \u6bcf\u4e2a Segment \u5185 HashEntry \u94fe<\/td>\n<td>\u76f4\u63a5\u662f Node \u6876\u6570\u7ec4&#xff0c;\u6876\u5185\u94fe\u8868\u6216\u7ea2\u9ed1\u6811<\/td>\n<\/tr>\n<tr>\n<td>\u9501\u5b9e\u73b0<\/td>\n<td>\u7ee7\u627f ReentrantLock \u7684 Segment&#xff0c;\u5199\u67d0\u6bb5\u9501\u67d0\u6bb5<\/td>\n<td>\u7a7a\u6876 CAS \u5199\u5165&#xff1b;\u975e\u7a7a\u6876 synchronized \u9501\u6876\u5934\u8282\u70b9<\/td>\n<\/tr>\n<tr>\n<td>\u9501\u7c92\u5ea6<\/td>\n<td>16 \u4e2a\u6bb5&#xff08;\u9ed8\u8ba4\u5e76\u53d1\u5ea6 16&#xff0c;\u5e76\u53d1\u5ea6\u4e0a\u9650 16&#xff09;<\/td>\n<td>\u6876\u6570&#xff08;\u53ef\u8fbe 1&lt;&lt;30&#xff09;&#xff0c;\u5e76\u53d1\u5ea6\u968f\u6269\u5bb9\u63d0\u5347<\/td>\n<\/tr>\n<tr>\n<td>\u8bfb\u64cd\u4f5c<\/td>\n<td>\u9700\u7ecf\u8fc7 volatile \u8bfb&#xff0c;\u4e0d\u52a0\u9501<\/td>\n<td>\u5b8c\u5168\u65e0\u9501&#xff08;volatile &#043; final &#043; \u4e0d\u53d8\u6027&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>\u6269\u5bb9<\/td>\n<td>\u6bb5\u5185\u6269\u5bb9&#xff0c;\u4e00\u6b21\u642c\u4e00\u6bb5&#xff0c;\u6bb5\u95f4\u4e92\u4e0d\u5f71\u54cd<\/td>\n<td>\u5168\u8868\u6269\u5bb9&#xff0c;\u4f46\u591a\u7ebf\u7a0b\u534f\u540c\u8fc1\u79fb&#xff08;\u65e7\u6876\u9010\u4e2a\u642c&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>\u8ba1\u6570<\/td>\n<td>\u6bb5\u5185 count \u76f8\u52a0<\/td>\n<td>baseCount &#043; CounterCell \u5206\u7247&#xff08;LongAdder \u601d\u60f3&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>key\/value<\/td>\n<td>\u5747\u4e0d\u5141\u8bb8 null<\/td>\n<td>\u5747\u4e0d\u5141\u8bb8 null<\/td>\n<\/tr>\n<tr>\n<td>size()<\/td>\n<td>\u4f9d\u6b21\u52a0\u6bb5 count&#xff0c;\u53ef\u80fd\u9501\u5404\u6bb5\u91cd\u7b97<\/td>\n<td>\u904d\u5386 CounterCell \u6c42\u548c&#xff0c;\u5f31\u4e00\u81f4<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4e3a\u4ec0\u4e48 JDK 8 \u6562\u653e\u5f03\u6210\u719f\u7684\u5206\u6bb5\u9501\u6a21\u578b&#xff1f;\u6838\u5fc3\u539f\u56e0&#xff1a;<\/p>\n<li>\u9501\u7c92\u5ea6\u66f4\u7ec6&#xff1a;\u5206\u6bb5\u9501\u7c92\u5ea6\u56fa\u5b9a 16 \u6bb5&#xff0c;\u70ed\u70b9\u6bb5\u7167\u6837\u6253\u67b6&#xff1b;\u6876\u9501\u7c92\u5ea6 &#061; \u6876\u6570&#xff0c;\u4e14\u53ea\u5728\u54c8\u5e0c\u51b2\u7a81&#xff08;\u6876\u975e\u7a7a&#xff09;\u65f6\u624d\u4e0a\u9501&#xff0c;\u65e0\u51b2\u7a81\u5199\u5165\u9000\u5316\u4e3a\u4e00\u6b21 CAS&#xff1b;<\/li>\n<li>\u8bfb\u5f7b\u5e95\u65e0\u9501&#xff1a;JDK 7 \u8bfb\u4e5f\u8981\u78b0\u5206\u6bb5\u9501\u7684 volatile \u57df&#xff1b;JDK 8 \u501f\u52a9 volatile \u6876\u5f15\u7528 &#043; Node \u5b57\u6bb5\u4e0d\u53ef\u53d8\/volatile \u8bed\u4e49\u505a\u5230\u65e0\u9501\u8bfb&#xff0c;\u8bfb\u662f\u5e76\u53d1\u573a\u666f\u6700\u5927\u5934&#xff1b;<\/li>\n<li>\u5de5\u7a0b\u987a\u52bf\u800c\u4e3a&#xff1a;JDK 6 \u4e4b\u540e synchronized \u5df2\u88ab JVM \u5168\u9762\u4f18\u5316&#xff08;\u504f\u5411\u9501\/\u8f7b\u91cf\u7ea7\u9501\/\u9501\u6d88\u9664&#xff09;&#xff0c;\u6876\u5934\u52a0 synchronized \u7684\u6210\u672c\u4f4e\u4e8e JDK 5 \u65f6\u4ee3&#xff0c;\u4ee3\u7801\u8fd8\u66f4\u7b80\u6d01&#xff1b;\u5b98\u65b9\u89e3\u91ca\u4e5f\u76f4\u8a00\u300csynchronized \u5728 JDK 6 \u540e\u6027\u80fd\u5df2\u4e0e ReentrantLock \u76f8\u5f53&#xff0c;\u800c\u9501\u7c92\u5ea6\u7ec6\u5316\u540e synchronized \u8db3\u4ee5\u80dc\u4efb\u300d\u3002<\/li>\n<hr \/>\n<h3>2. \u6574\u4f53\u8bbe\u8ba1\u603b\u89c8<\/h3>\n<h4>2.1 \u6570\u636e\u5e03\u5c40<\/h4>\n<p>JDK 8 \u7684\u7269\u7406\u7ed3\u6784&#xff08;\u6876\u6570\u7ec4\u91cc\u653e\u56db\u79cd\u8282\u70b9\u4e4b\u4e00&#xff0c;\u6e32\u67d3\u7248\u7ed3\u6784\u56fe&#xff09;&#xff1a; <img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/09\/20260909185701-6aa1abfdd82fc.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<p>\u6876\u5185\u8282\u70b9\u7684 hash \u5b57\u6bb5\u88ab\u590d\u7528\u4e3a\u7c7b\u578b\u6807\u8bb0&#xff08;\u8fd9\u662f\u7406\u89e3\u4e00\u5207\u5206\u6d3e\u903b\u8f91\u7684\u94a5\u5319&#xff09;&#xff1a;<\/p>\n<table>\n<tr>hash \u503c\u8282\u70b9\u7c7b\u578b\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>\u2265 0&#xff08;\u771f\u5b9e\u54c8\u5e0c&#xff09;<\/td>\n<td>Node \/ TreeNode \u94fe\u8868<\/td>\n<td>\u666e\u901a\u952e\u503c\u8282\u70b9<\/td>\n<\/tr>\n<tr>\n<td>-1&#xff08;MOVED&#xff09;<\/td>\n<td>ForwardingNode<\/td>\n<td>\u8be5\u6876\u5df2\u8fc1\u79fb\u5b8c\u6210&#xff0c;\u6307\u5411\u65b0\u8868\u5bf9\u5e94\u6876<\/td>\n<\/tr>\n<tr>\n<td>-2&#xff08;TREEBIN&#xff09;<\/td>\n<td>TreeBin<\/td>\n<td>\u6876\u5185\u662f\u7ea2\u9ed1\u6811&#xff08;TreeBin \u662f\u6811\u6839\u5bb9\u5668&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>-3&#xff08;RESERVED&#xff09;<\/td>\n<td>ReservationNode<\/td>\n<td>computeIfAbsent \u7684\u5360\u4f4d\u8282\u70b9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4>2.2 put \u4e3b\u6d41\u7a0b\u603b\u89c8<\/h4>\n<p>\u5148\u5efa\u7acb\u5168\u5c40\u89c6\u89d2&#xff0c;4~5 \u7ae0\u518d\u9010\u6bb5\u5bf9\u7167\u6e90\u7801&#xff1a;<\/p>\n<p>put(key, value)<br \/>\n \u2514\u2500 putVal(key, value, onlyIfAbsent&#061;false)<br \/>\n     \u251c\u2500 \u2460 key\/value \u5224\u7a7a&#xff08;null \u76f4\u63a5 NPE&#xff09;<br \/>\n     \u251c\u2500 \u2461 table \u4e3a null&#xff1f;\u2500\u2500\u25ba initTable() \u521d\u59cb\u5316&#xff08;CAS \u62a2\u521d\u59cb\u5316\u6743&#xff0c;\u89c1 3.2&#xff09;<br \/>\n     \u251c\u2500 \u2462 \u5b9a\u4f4d\u6876&#xff1a;i &#061; (table.length-1) &amp; spread(hash)<br \/>\n     \u251c\u2500 \u2463 \u6876\u4e3a null&#xff1f;\u2500\u2500\u25ba casTabAt \u76f4\u63a5\u653e\u65b0 Node&#xff08;\u539f\u5b50&#xff09;&#xff0c;\u6210\u529f\u5373\u6536\u5de5<br \/>\n     \u251c\u2500 \u2464 \u6876\u5934 hash &#061;&#061; MOVED&#xff1f;\u2500\u2500\u25ba helpTransfer()&#xff1a;\u653e\u4e0b\u81ea\u5df1\u7684\u5199&#xff0c;\u5148\u5e2e\u5fd9\u6269\u5bb9<br \/>\n     \u251c\u2500 \u2465 \u5426\u5219 synchronized(\u6876\u5934\u8282\u70b9 f)&#xff1a;<br \/>\n     \u2502     \u251c\u2500 \u518d\u6b21\u6821\u9a8c\u6876\u5934\u6ca1\u53d8&#xff08;double-check&#xff09;<br \/>\n     \u2502     \u251c\u2500 f \u662f\u666e\u901a Node&#xff1a;\u904d\u5386\u94fe\u8868<br \/>\n     \u2502     \u2502     \u251c\u2500 \u627e\u5230\u540c key&#xff08;equals&#xff09;\u2500\u2500\u25ba \u8986\u76d6 value&#xff08;binCount \u8bb0\u5f55\u4f4d\u7f6e&#xff09;<br \/>\n     \u2502     \u2502     \u2514\u2500 \u6ca1\u627e\u5230 \u2500\u2500\u25ba \u94fe\u8868\u5c3e\u90e8\u63d2\u5165\u65b0 Node<br \/>\n     \u2502     \u251c\u2500 f \u662f TreeBin&#xff1a;\u8c03\u7528 putTreeVal \u63d2\u5165\/\u8986\u76d6\u7ea2\u9ed1\u6811<br \/>\n     \u2502     \u2514\u2500 \u8bb0\u5f55 binCount&#xff08;\u94fe\u8868\u957f\u5ea6&#xff0c;\u7528\u4e8e\u89e6\u53d1\u6811\u5316&#xff09;<br \/>\n     \u251c\u2500 \u2466 binCount \u2265 8&#xff08;TREEIFY_THRESHOLD&#xff09;\u2500\u2500\u25ba treeifyBin() \u5c1d\u8bd5\u6811\u5316<br \/>\n     \u2502     &#xff08;\u6ce8\u610f&#xff1a;\u6876\u6570\u7ec4 &lt; 64 \u65f6\u5148\u6269\u5bb9\u800c\u975e\u6811\u5316&#xff09;<br \/>\n     \u2514\u2500 \u2467 addCount(1L, binCount) \u8ba1\u6570&#xff0c;\u53ef\u80fd\u89e6\u53d1\u6269\u5bb9&#xff08;\u89c1\u7b2c 5\u30016 \u7ae0&#xff09;<\/p>\n<h4>2.3 \u6838\u5fc3\u5b57\u6bb5\u8868<\/h4>\n<p><span class=\"token comment\">\/\/ JDK 8 \u5b9e\u9645\u5b57\u6bb5&#xff08;\u8282\u9009\u81ea ConcurrentHashMap.java&#xff09;<\/span><br \/>\n<span class=\"token keyword\">transient<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> table<span class=\"token punctuation\">;<\/span>        <span class=\"token comment\">\/\/ \u6876\u6570\u7ec4&#xff0c;\u61d2\u521d\u59cb\u5316<\/span><br \/>\n<span class=\"token keyword\">private<\/span> <span class=\"token keyword\">transient<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> nextTable<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u6269\u5bb9\u4e2d\u7684\u65b0\u8868&#xff08;\u53ea\u6709\u6269\u5bb9\u671f\u975e null&#xff09;<\/span><\/p>\n<p><span class=\"token keyword\">private<\/span> <span class=\"token keyword\">transient<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token keyword\">long<\/span> baseCount<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u57fa\u7840\u8ba1\u6570&#xff08;\u65e0\u7ade\u4e89\u65f6\u76f4\u63a5 CAS \u66f4\u65b0&#xff09;<\/span><br \/>\n<span class=\"token keyword\">private<\/span> <span class=\"token keyword\">transient<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token keyword\">int<\/span> sizeCtl<span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/\/ \u5e76\u53d1\u63a7\u5236\u603b\u5f00\u5173&#xff08;\u89c1 2.4 \u8868&#xff09;<\/span><br \/>\n<span class=\"token keyword\">private<\/span> <span class=\"token keyword\">transient<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token keyword\">int<\/span> transferIndex<span class=\"token punctuation\">;<\/span><span class=\"token comment\">\/\/ \u6269\u5bb9\u533a\u95f4\u6e38\u6807&#xff1a;\u4e0b\u4e00\u4e2a\u5f85\u8fc1\u79fb\u6876\u7684\u8d77\u70b9<\/span><br \/>\n<span class=\"token keyword\">private<\/span> <span class=\"token keyword\">transient<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token keyword\">int<\/span> cellsBusy<span class=\"token punctuation\">;<\/span>    <span class=\"token comment\">\/\/ CounterCell \u6570\u7ec4\u6269\u5bb9\/\u521d\u59cb\u5316\u7684\u9501&#xff08;0\/1&#xff09;<\/span><br \/>\n<span class=\"token keyword\">private<\/span> <span class=\"token keyword\">transient<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token class-name\">CounterCell<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> counterCells<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u8ba1\u6570\u5206\u7247&#xff08;\u4e89\u7528\u5206\u6563&#xff09;<\/span><\/p>\n<table>\n<tr>\u5b57\u6bb5\u7c7b\u578b\u804c\u8d23<\/tr>\n<tbody>\n<tr>\n<td>table<\/td>\n<td>Node[]<\/td>\n<td>\u54c8\u5e0c\u6876\u6570\u7ec4&#xff0c;volatile \u4fdd\u8bc1\u6269\u5bb9\u540e\u65b0\u8868\u7acb\u5373\u53ef\u89c1<\/td>\n<\/tr>\n<tr>\n<td>nextTable<\/td>\n<td>Node[]<\/td>\n<td>\u6269\u5bb9\u76ee\u6807\u8868&#xff08;\u5bb9\u91cf\u7ffb\u500d&#xff09;&#xff0c;\u4ec5\u6269\u5bb9\u671f\u95f4\u975e null<\/td>\n<\/tr>\n<tr>\n<td>baseCount<\/td>\n<td>long<\/td>\n<td>\u65e0\u7ade\u4e89\u65f6\u7684\u8ba1\u6570\u7d2f\u52a0\u57fa\u5e95<\/td>\n<\/tr>\n<tr>\n<td>sizeCtl<\/td>\n<td>int<\/td>\n<td>\u72b6\u6001\u673a\u6838\u5fc3&#xff1a;\u521d\u59cb\u5bb9\u91cf\/\u6269\u5bb9\u9608\u503c\/\u521d\u59cb\u5316\u6807\u8bb0\/\u6269\u5bb9\u7ebf\u7a0b\u6570&#xff0c;\u89c1\u4e0b<\/td>\n<\/tr>\n<tr>\n<td>transferIndex<\/td>\n<td>int<\/td>\n<td>\u6269\u5bb9\u65f6\u4ece table.length \u9012\u51cf&#xff0c;\u591a\u7ebf\u7a0b\u4ece\u8fd9\u91cc\u9886\u53d6\u8fc1\u79fb\u533a\u95f4<\/td>\n<\/tr>\n<tr>\n<td>cellsBusy<\/td>\n<td>int<\/td>\n<td>CounterCell \u8868\u521d\u59cb\u5316\u7684\u81ea\u65cb\u9501&#xff08;0&#061;\u7a7a\u95f2&#xff0c;1&#061;\u88ab\u5360\u7528&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>counterCells<\/td>\n<td>CounterCell[]<\/td>\n<td>\u8ba1\u6570\u5206\u7247\u6570\u7ec4&#xff0c;\u964d\u4f4e\u70ed\u70b9\u7ade\u4e89<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4>2.4 sizeCtl \u7684\u8bed\u4e49<\/h4>\n<p>sizeCtl \u662f CHM \u7684\u300c\u5927\u8111\u300d&#xff0c;\u4e00\u4e2a int \u5728\u4e0d\u540c\u9636\u6bb5\u8868\u8fbe\u56db\u79cd\u542b\u4e49\u2014\u2014\u9762\u8bd5\u5fc5\u8003\u70b9&#xff1a;<\/p>\n<table>\n<tr>sizeCtl \u53d6\u503c\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>0<\/td>\n<td>\u8868\u672a\u521d\u59cb\u5316&#xff0c;\u4e14\u6784\u9020\u65f6\u672a\u6307\u5b9a\u5bb9\u91cf&#xff08;\u7528\u9ed8\u8ba4 16&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>&gt; 0<\/td>\n<td>\u8868\u672a\u521d\u59cb\u5316 \u2192 \u521d\u59cb\u5bb9\u91cf&#xff1b;\u8868\u5df2\u521d\u59cb\u5316 \u2192 \u6269\u5bb9\u9608\u503c&#xff08;0.75 * \u5bb9\u91cf&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>-1<\/td>\n<td>\u6709\u7ebf\u7a0b\u6b63\u5728\u8fdb\u884c initTable \u521d\u59cb\u5316&#xff08;\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u80fd CAS \u6210\u529f&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>&lt; -1&#xff08;\u5982 -2&#xff09;<\/td>\n<td>\u6b63\u5728\u6269\u5bb9&#xff1a;-(1 &#043; \u53c2\u4e0e\u6269\u5bb9\u7684\u7ebf\u7a0b\u6570)&#xff0c;\u5982 -2 \u8868\u793a\u5df2\u6709 1 \u4e2a\u7ebf\u7a0b\u5728\u8fc1\u79fb<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span class=\"token comment\">\/\/ initTable \u91cc\u62a2\u521d\u59cb\u5316\u6743\u7684\u6838\u5fc3 CAS&#xff08;\u8282\u9009&#xff09;<\/span><br \/>\n<span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>sc <span class=\"token operator\">&#061;<\/span> sizeCtl<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span>                       <span class=\"token comment\">\/\/ sizeCtl \u4e3a\u8d1f &#061; \u522b\u4eba\u5728\u521d\u59cb\u5316\/\u6269\u5bb9<\/span><br \/>\n    <span class=\"token class-name\">Thread<\/span><span class=\"token punctuation\">.<\/span><span class=\"token keyword\">yield<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">U<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">compareAndSwapInt<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">SIZECTL<\/span><span class=\"token punctuation\">,<\/span> sc<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>   <span class=\"token comment\">\/\/ \u628a 0\/\u5bb9\u91cf \u6362\u6210 -1&#xff0c;\u62a2\u6743\u6210\u529f<\/span><br \/>\n    <span class=\"token keyword\">try<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>tab <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span> tab<span class=\"token punctuation\">.<\/span>length <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> n <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">(<\/span>sc <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">?<\/span> sc <span class=\"token operator\">:<\/span> <span class=\"token constant\">DEFAULT_CAPACITY<\/span><span class=\"token punctuation\">;<\/span>     <span class=\"token comment\">\/\/ \u5bb9\u91cf\u53d6\u81ea\u6784\u9020\u53c2\u6570<\/span><br \/>\n            <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n            tab <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token punctuation\">[<\/span>n<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            sizeCtl <span class=\"token operator\">&#061;<\/span> n <span class=\"token operator\">&#8211;<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;&gt;&gt;<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>                      <span class=\"token comment\">\/\/ \u5199\u56de\u6269\u5bb9\u9608\u503c 0.75n<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">finally<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u5931\u8d25\u5219\u6062\u590d<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5173\u952e\u8ba4\u77e5&#xff1a;CHM \u7684\u6240\u6709\u5e76\u53d1\u534f\u4f5c&#xff08;\u521d\u59cb\u5316\u3001\u6269\u5bb9\u8ba4\u9886\u3001\u8ba1\u6570\u5206\u7247&#xff09;\u90fd\u56f4\u7ed5\u300c\u5bf9\u4e00\u4e2a\u5171\u4eab int \u7684 CAS\u300d\u5c55\u5f00&#xff0c;\u6ca1\u6709\u4e00\u628a\u5168\u5c40\u9501\u2014\u2014\u8fd9\u5c31\u662f\u5b83\u9ad8\u5e76\u53d1\u7684\u6839\u6e90\u3002\u51e1\u662f\u770b\u5230\u5bf9 sizeCtl\/cellsBusy\/transferIndex \u7684 compareAndSwapInt&#xff0c;\u90fd\u662f\u300c\u5206\u5e03\u5f0f\u534f\u4f5c\u70b9\u300d\u3002<\/p>\n<h3>3. \u5165\u53e3\u4e0e\u6784\u9020<\/h3>\n<h4>3.1 \u7c7b\u58f0\u660e\u4e0e\u91cd\u8981\u5e38\u91cf<\/h4>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ConcurrentHashMap<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token keyword\">extends<\/span> <span class=\"token class-name\">AbstractMap<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><br \/>\n    <span class=\"token keyword\">implements<\/span> <span class=\"token class-name\">ConcurrentMap<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Serializable<\/span> <span class=\"token punctuation\">{<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u2500\u2500 \u5bb9\u91cf\u4e0e\u9608\u503c\u5e38\u91cf \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500<\/span><br \/>\n    <span class=\"token keyword\">private<\/span> <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">DEFAULT_CAPACITY<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">16<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">private<\/span> <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">MAXIMUM_CAPACITY<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span> <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token number\">30<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">private<\/span> <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">float<\/span> <span class=\"token constant\">LOAD_FACTOR<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0.75f<\/span><span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/\/ \u4ec5\u6784\u9020\u53c2\u6570\u517c\u5bb9\u7528&#xff08;JDK8 \u5185\u90e8\u4e0d\u7528\u5b83\u7b97\u9608\u503c&#xff09;<\/span><br \/>\n    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">TREEIFY_THRESHOLD<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">8<\/span><span class=\"token punctuation\">;<\/span>              <span class=\"token comment\">\/\/ \u6876\u5185\u94fe\u8868\u957f\u5ea6\u8fbe\u5230 8 \u2192 \u5c1d\u8bd5\u6811\u5316<\/span><br \/>\n    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">UNTREEIFY_THRESHOLD<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">6<\/span><span class=\"token punctuation\">;<\/span>            <span class=\"token comment\">\/\/ \u6269\u5bb9\u62c6\u6876\u540e\u6811\u8282\u70b9 \u2264 6 \u2192 \u9000\u5316\u4e3a\u94fe\u8868<\/span><br \/>\n    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">MIN_TREEIFY_CAPACITY<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">64<\/span><span class=\"token punctuation\">;<\/span>          <span class=\"token comment\">\/\/ \u6876\u6570\u7ec4 &lt; 64 \u65f6\u5148\u6269\u5bb9&#xff0c;\u4e0d\u6811\u5316<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u2500\u2500 \u6876\u5934\u8282\u70b9 hash \u5b57\u6bb5\u7684\u7279\u6b8a\u6807\u8bb0 \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500<\/span><br \/>\n    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">MOVED<\/span>     <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ ForwardingNode&#xff1a;\u6876\u5df2\u8fc1\u79fb<\/span><br \/>\n    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">TREEBIN<\/span>   <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">2<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ TreeBin&#xff1a;\u6876\u5185\u662f\u7ea2\u9ed1\u6811<\/span><br \/>\n    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">RESERVED<\/span>  <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">3<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ ReservationNode&#xff1a;computeIfAbsent \u5360\u4f4d<\/span><br \/>\n    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">HASH_BITS<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0x7fffffff<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u7b26\u53f7\u4f4d\u6e05\u96f6&#xff0c;\u4fdd\u8bc1 hash \u975e\u8d1f<\/span><\/p>\n<p>    <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">NCPU<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token class-name\">Runtime<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">getRuntime<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">availableProcessors<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4e24\u4e2a\u53cd\u76f4\u89c9\u70b9\u5148\u8bb0\u4f4f&#xff1a;<\/p>\n<li>LOAD_FACTOR &#061; 0.75f \u5728 JDK 8 \u91cc\u53ea\u662f\u6784\u9020\u5668\u53c2\u6570\u517c\u5bb9&#xff08;\u628a\u5bb9\u91cf\u6362\u7b97\u6210\u7acb\u5373\u521d\u59cb\u5316\u7684 n&#xff09;&#xff0c;\u6269\u5bb9\u9608\u503c\u4e00\u5f8b\u5199\u6210 sizeCtl &#061; n &#8211; (n &gt;&gt;&gt; 2)&#xff0c;\u5373 0.75n \u7684\u4f4d\u8fd0\u7b97\u5199\u6cd5&#xff1b;<\/li>\n<li>\u666e\u901a\u952e\u503c\u8282\u70b9\u7684 hash \u5b57\u6bb5\u5b58\u653e spread() \u4e4b\u540e\u7684\u503c&#xff0c;\u5fc5\u7136 \u2265 0\u2014\u2014\u6240\u4ee5\u5224\u65ad\u6876\u5934\u7c7b\u578b\u53ea\u9700\u770b\u7b26\u53f7\u4f4d\u3002<\/li>\n<h4>3.2 \u6784\u9020\u5668\u4e0e\u61d2\u521d\u59cb\u5316<\/h4>\n<p><span class=\"token comment\">\/\/ \u65e0\u53c2\u6784\u9020&#xff1a;\u4ec0\u4e48\u90fd\u4e0d\u505a&#xff08;\u5173\u952e&#xff01;\u8868\u662f\u61d2\u521d\u59cb\u5316\u7684&#xff09;<\/span><br \/>\n<span class=\"token keyword\">public<\/span> <span class=\"token class-name\">ConcurrentHashMap<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u6307\u5b9a\u5bb9\u91cf&#xff1a;\u53ea\u628a\u5b83\u6362\u7b97\u6210 2 \u7684\u5e42\u5b58\u8fdb sizeCtl&#xff0c;\u4ecd\u7136\u4e0d\u5efa\u8868<\/span><br \/>\n<span class=\"token keyword\">public<\/span> <span class=\"token class-name\">ConcurrentHashMap<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> initialCapacity<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>initialCapacity <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">throw<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">IllegalArgumentException<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> cap <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>initialCapacity <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token constant\">MAXIMUM_CAPACITY<\/span> <span class=\"token operator\">&gt;&gt;&gt;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">?<\/span><br \/>\n               <span class=\"token constant\">MAXIMUM_CAPACITY<\/span> <span class=\"token operator\">:<\/span><br \/>\n               <span class=\"token function\">tableSizeFor<\/span><span class=\"token punctuation\">(<\/span>initialCapacity <span class=\"token operator\">&#043;<\/span> <span class=\"token punctuation\">(<\/span>initialCapacity <span class=\"token operator\">&gt;&gt;&gt;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">this<\/span><span class=\"token punctuation\">.<\/span>sizeCtl <span class=\"token operator\">&#061;<\/span> cap<span class=\"token punctuation\">;<\/span>          <span class=\"token comment\">\/\/ \u6b64\u65f6 sizeCtl &#061; \u76ee\u6807\u5bb9\u91cf&#xff08;\u6b63\u6570&#xff09;&#xff0c;\u4e0d\u662f\u9608\u503c<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u8868\u771f\u6b63\u5efa\u7acb\u53d1\u751f\u5728\u7b2c\u4e00\u6b21 put \u7684 initTable()<\/span><\/p>\n<p>initTable \u7684\u5e76\u53d1\u6b63\u786e\u6027&#xff08;\u89c1 2.4 \u4ee3\u7801&#xff09;&#xff1a;\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u9996\u6b21 put&#xff0c;\u90fd\u53d1\u73b0 table &#061;&#061; null&#xff0c;\u4f46\u53ea\u6709\u4e00\u4e2a\u80fd\u628a sizeCtl \u4ece 0 CAS \u6210 -1\u2014\u2014\u62a2\u5230\u8005\u5efa\u8868&#xff0c;\u5176\u4f59\u7ebf\u7a0b Thread.yield() \u81ea\u65cb\u7b49\u5f85&#xff0c;\u7b49 sizeCtl \u53d8\u6210\u6b63\u7684\u9608\u503c\u540e\u9000\u51fa\u3002<\/p>\n<p>\u5173\u952e\u8ba4\u77e5&#xff1a;CHM \u6ca1\u6709\u300c\u6784\u9020\u5373\u5206\u914d\u300d\u7684\u4f20\u7edf&#xff0c;\u5185\u5b58\u5360\u7528\u4e0e\u542f\u52a8\u6210\u672c\u90fd\u88ab\u63a8\u8fdf\u5230\u7b2c\u4e00\u6b21\u5199\u5165\u3002\u6784\u9020\u4f20\u5165\u7684 initialCapacity \u4f1a\u88ab\u5f53\u4f5c\u300c\u9884\u671f\u542b\u5143\u7d20\u6570\u300d&#xff0c;\u5185\u90e8\u5148\u52a0 50% \u518d\u53d6 2 \u7684\u5e42&#xff0c;\u6240\u4ee5 new ConcurrentHashMap&lt;&gt;(100) \u5b9e\u9645\u5bb9\u91cf 256\u2014\u2014\u907f\u514d\u4e2d\u9014\u6269\u5bb9\u3002<\/p>\n<h4>3.3 Node \u5185\u90e8\u7c7b\u4f53\u7cfb<\/h4>\n<p>\u4e94\u4e2a\u5185\u90e8\u7c7b\u5206\u5de5\u660e\u786e&#xff08;\u7c7b\u5173\u7cfb\u56fe\u89c1\u7b2c 9 \u7ae0&#xff09;&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ 1. \u666e\u901a\u8282\u70b9&#xff1a;\u6876\u5185\u94fe\u8868\u5143\u7d20&#xff0c;val\/next \u90fd\u662f volatile<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token keyword\">implements<\/span> <span class=\"token class-name\">Map<span class=\"token punctuation\">.<\/span>Entry<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> hash<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">final<\/span> <span class=\"token class-name\">K<\/span> key<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">volatile<\/span> <span class=\"token class-name\">V<\/span> val<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">volatile<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> next<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ 2. \u94fe\u8868\u8f6c\u6811\u65f6\u7684\u4e2d\u95f4\u8282\u70b9&#xff08;\u5148\u6210\u53cc\u5411\u94fe\u8868&#xff0c;\u518d\u642d\u7ea2\u9ed1\u6811&#xff09;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token keyword\">extends<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> parent<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> left<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> right<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> prev<span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/\/ \u53cc\u5411\u94fe\u8868\u6307\u9488&#xff08;\u6811\u9000\u5316\u6210\u94fe\u8868\u8981\u9760\u5b83&#xff09;<\/span><br \/>\n    <span class=\"token keyword\">boolean<\/span> red<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ 3. \u6811\u7684\u6876\u5bb9\u5668&#xff08;hash \u56fa\u5b9a -2&#xff09;&#xff0c;\u6301\u6709\u7ea2\u9ed1\u6811\u6839 &#043; \u9996\u8282\u70b9\u94fe\u8868 &#043; \u8bfb\u5199\u9501\u72b6\u6001<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">TreeBin<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token keyword\">extends<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> root<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">volatile<\/span> <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> first<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u94fe\u5934&#xff1a;\u5199\u9501\u7ade\u4e89\u65f6\u8bfb\u9000\u5316\u4e3a\u7ebf\u6027\u626b\u63cf<\/span><br \/>\n    <span class=\"token keyword\">volatile<\/span> <span class=\"token keyword\">int<\/span> lockState<span class=\"token punctuation\">;<\/span>         <span class=\"token comment\">\/\/ \u7b80\u5316\u8bfb\u5199\u9501&#xff0c;\u89c1 8.2<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ 4. \u6269\u5bb9\u8f6c\u53d1\u8282\u70b9&#xff08;hash \u56fa\u5b9a -1&#xff09;&#xff1a;\u65e7\u6876\u8fc1\u79fb\u5b8c\u6210\u540e\u5360\u4f4d&#xff0c;\u6307\u5411\u65b0\u8868<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ForwardingNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token keyword\">extends<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">final<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> nextTable<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token class-name\">ForwardingNode<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">super<\/span><span class=\"token punctuation\">(<\/span><span class=\"token constant\">MOVED<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">this<\/span><span class=\"token punctuation\">.<\/span>nextTable <span class=\"token operator\">&#061;<\/span> tab<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ 5. computeIfAbsent \u7684\u5360\u4f4d\u8282\u70b9&#xff08;hash \u56fa\u5b9a -3&#xff09;&#xff0c;\u9632\u6b62\u9012\u5f52\u8ba1\u7b97\u540c\u4e00 key<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ReservationNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token keyword\">extends<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">ReservationNode<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">super<\/span><span class=\"token punctuation\">(<\/span><span class=\"token constant\">RESERVED<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<hr \/>\n<h3>4. putVal \u5206\u6b65\u8be6\u89e3<\/h3>\n<p>put \u6700\u7ec8\u8c03\u7528 putVal(key, value, onlyIfAbsent)&#xff0c;\u4e0b\u9762\u6309\u6e90\u7801\u987a\u5e8f\u5206\u6b65\u62c6\u89e3\u3002<\/p>\n<h4>4.1 \u5b9a\u4f4d\u4e0e\u7a7a\u6876 CAS<\/h4>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token class-name\">V<\/span> <span class=\"token function\">put<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">K<\/span> key<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">V<\/span> value<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">return<\/span> <span class=\"token function\">putVal<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">,<\/span> value<span class=\"token punctuation\">,<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">final<\/span> <span class=\"token class-name\">V<\/span> <span class=\"token function\">putVal<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">K<\/span> key<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">V<\/span> value<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">boolean<\/span> onlyIfAbsent<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>key <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span> value <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">throw<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">NullPointerException<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u2460 \u53cc null \u62d2\u7edd<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> hash <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">spread<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">.<\/span><span class=\"token function\">hashCode<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>                                    <span class=\"token comment\">\/\/ \u2461 \u6270\u52a8\u54c8\u5e0c<\/span><\/p>\n<p>    <span class=\"token keyword\">int<\/span> binCount <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab <span class=\"token operator\">&#061;<\/span> table<span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                                     <span class=\"token comment\">\/\/ \u2462 \u81ea\u65cb&#xff08;CAS \u5931\u8d25\u4f1a\u91cd\u6765&#xff09;<\/span><br \/>\n        <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> f<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">int<\/span> n<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">,<\/span> fh<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>tab <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;<\/span> tab<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            tab <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">initTable<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>                                            <span class=\"token comment\">\/\/ \u2463 \u61d2\u5efa\u8868&#xff08;3.2&#xff09;<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>f <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#8211;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&amp;<\/span> hash<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>          <span class=\"token comment\">\/\/ \u2464 \u5b9a\u4f4d\u6876\u4e14\u6876\u7a7a<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">casTabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                         <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">(<\/span>hash<span class=\"token punctuation\">,<\/span> key<span class=\"token punctuation\">,<\/span> value<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span>          <span class=\"token comment\">\/\/ \u2465 \u7a7a\u6876 CAS \u76f4\u653e<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span>                                                    <span class=\"token comment\">\/\/ \u2705 \u6210\u529f\u5373\u5b8c\u6210&#xff08;\u65e0\u9501&#xff01;&#xff09;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>fh <span class=\"token operator\">&#061;<\/span> f<span class=\"token punctuation\">.<\/span>hash<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token constant\">MOVED<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            tab <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">helpTransfer<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> f<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>                                   <span class=\"token comment\">\/\/ \u2466 \u6876\u5df2\u8fc1\u79fb \u2192 \u5e2e\u5fd9\u6269\u5bb9<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span>                                                           <span class=\"token comment\">\/\/ \u2467 \u6876\u975e\u7a7a&#xff1a;\u6876\u5934\u52a0\u9501&#xff08;4.3&#xff09;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token function\">addCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">1L<\/span><span class=\"token punctuation\">,<\/span> binCount<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>                                               <span class=\"token comment\">\/\/ \u2468 \u8ba1\u6570<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u8981\u70b9&#xff1a;<\/p>\n<ul>\n<li>spread()&#xff1a;(h ^ (h &gt;&gt;&gt; 16)) &amp; HASH_BITS\u2014\u2014\u9ad8\u4f4d\u53c2\u4e0e\u4f4e\u4f4d\u8ba1\u7b97&#xff08;hashCode \u4f4e\u4f4d\u76f8\u540c\u7684 key \u4e0d\u518d\u624e\u5806&#xff09;&#xff0c;\u540c\u65f6\u628a\u7b26\u53f7\u4f4d\u62b9\u6389\u4fdd\u8bc1 hash \u2265 0&#xff08;\u5426\u5219\u4f1a\u4e0e MOVED \u7b49\u8d1f\u6570\u6807\u8bb0\u51b2\u7a81&#xff09;&#xff1b;<\/li>\n<li>tabAt \/ casTabAt&#xff1a;\u5bf9\u6876\u6570\u7ec4\u5143\u7d20\u7684 volatile \u8bfb\u5199\u4e0e CAS&#xff0c;\u901a\u8fc7 Unsafe.getObjectVolatile \u5b9e\u73b0&#xff08;\u6570\u7ec4\u5143\u7d20\u65e0\u6cd5\u76f4\u63a5\u7528 volatile \u4fee\u9970&#xff09;&#xff1b;<\/li>\n<li>\u7a7a\u6876\u5199\u5165\u5168\u7a0b\u65e0\u9501&#xff1a;\u591a\u7ebf\u7a0b\u5404\u5199\u5404\u7684\u7a7a\u6876&#xff0c;\u5404\u81ea CAS \u6210\u529f&#xff0c;\u4e92\u4e0d\u5e72\u6270\u2014\u2014\u8fd9\u662f JDK 8 \u5e76\u53d1\u5ea6\u7684\u5929\u82b1\u677f&#xff08;&#061; \u6876\u6570&#xff09;\u3002<\/li>\n<\/ul>\n<h4>4.2 MOVED \u4e0e\u534f\u52a9\u6269\u5bb9<\/h4>\n<p>f.hash &#061;&#061; MOVED \u8bf4\u660e\u8fd9\u4e2a\u6876\u5df2\u88ab\u8fc1\u79fb\u8d70&#xff0c;\u6876\u91cc\u653e\u7684\u662f ForwardingNode&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ ForwardingNode \u7684 find \u4f1a\u628a\u67e5\u8be2\u8f6c\u53d1\u5230\u65b0\u8868<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ForwardingNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token keyword\">extends<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">final<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> nextTable<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> h<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Object<\/span> k<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        outer<span class=\"token operator\">:<\/span> <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab <span class=\"token operator\">&#061;<\/span> nextTable<span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>   <span class=\"token comment\">\/\/ \u8bfb\u64cd\u4f5c\u8df3\u5230\u65b0\u8868\u7ee7\u7eed\u627e<\/span><br \/>\n            <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5199\u5165\u65b9\u770b\u5230 MOVED \u4e0d\u4f1a\u50bb\u7b49&#xff0c;\u800c\u662f\u52a0\u5165\u8fc1\u79fb\u961f\u4f0d&#xff08;helpTransfer&#xff0c;5.2 \u8be6\u8ff0&#xff09;\u2014\u2014\u5199\u7ebf\u7a0b\u5728\u65e7\u8868\u7ee7\u7eed\u5199\u53ef\u80fd\u4e22\u5931\u65b0\u63d2\u5165\u7684\u6570\u636e&#xff0c;\u6240\u4ee5\u5fc5\u987b\u5148\u628a\u65e7\u6876\u642c\u5b8c\u3002\u8fd9\u4e5f\u662f CHM \u7684\u4e00\u4e2a\u8bbe\u8ba1\u54f2\u5b66&#xff1a;\u6bcf\u4e2a\u64cd\u4f5c\u8005\u90fd\u6709\u4e49\u52a1\u63a8\u8fdb\u5168\u5c40\u72b6\u6001&#xff0c;\u800c\u4e0d\u662f\u65c1\u89c2\u3002<\/p>\n<h4>4.3 \u6876\u5934\u52a0\u9501\u5199\u5165<\/h4>\n<p>\u6876\u975e\u7a7a\u4e14\u975e MOVED \u65f6\u8fdb\u5165\u6838\u5fc3\u5206\u652f\u2014\u2014\u9501\u6876\u5934\u8282\u70b9&#xff1a;<\/p>\n<p><span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">V<\/span> oldVal <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">synchronized<\/span> <span class=\"token punctuation\">(<\/span>f<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                        <span class=\"token comment\">\/\/ \u2460 \u9501\u7c92\u5ea6 &#061; \u5355\u4e2a\u6876\u7684\u6876\u5934\u8282\u70b9<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> f<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>             <span class=\"token comment\">\/\/ \u2461 double-check&#xff1a;\u7b49\u9501\u671f\u95f4\u6876\u5934\u53ef\u80fd\u5df2\u88ab\u642c\u8d70\/\u66ff\u6362<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fh <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                    <span class=\"token comment\">\/\/ \u2462 \u666e\u901a\u94fe\u8868\u6876<\/span><br \/>\n                binCount <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> e <span class=\"token operator\">&#061;<\/span> f<span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>binCount<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token class-name\">K<\/span> ek<span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>e<span class=\"token punctuation\">.<\/span>hash <span class=\"token operator\">&#061;&#061;<\/span> hash <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>ek <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span>key<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> key <span class=\"token operator\">||<\/span><br \/>\n                         <span class=\"token punctuation\">(<\/span>ek <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">&amp;&amp;<\/span> key<span class=\"token punctuation\">.<\/span><span class=\"token function\">equals<\/span><span class=\"token punctuation\">(<\/span>ek<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        oldVal <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span>val<span class=\"token punctuation\">;<\/span>       <span class=\"token comment\">\/\/ \u2463 \u627e\u5230\u540c key \u2192 \u8986\u76d6<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>onlyIfAbsent<span class=\"token punctuation\">)<\/span> e<span class=\"token punctuation\">.<\/span>val <span class=\"token operator\">&#061;<\/span> value<span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><br \/>\n                    <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> pred <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>e <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span>next<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>   <span class=\"token comment\">\/\/ \u2464 \u5c3e\u63d2\u65b0\u8282\u70b9<\/span><br \/>\n                        pred<span class=\"token punctuation\">.<\/span>next <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">(<\/span>hash<span class=\"token punctuation\">,<\/span> key<span class=\"token punctuation\">,<\/span> value<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>f <span class=\"token keyword\">instanceof<\/span> <span class=\"token class-name\">TreeBin<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>  <span class=\"token comment\">\/\/ \u2465 \u7ea2\u9ed1\u6811\u6876&#xff1a;\u4ea4\u7ed9\u6811\u53bb\u63d2&#xff08;8.3&#xff09;<\/span><br \/>\n                <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> p<span class=\"token punctuation\">;<\/span><br \/>\n                binCount <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>p <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">TreeBin<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">)<\/span>f<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">putTreeVal<\/span><span class=\"token punctuation\">(<\/span>hash<span class=\"token punctuation\">,<\/span> key<span class=\"token punctuation\">,<\/span> value<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    oldVal <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">.<\/span>val<span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>onlyIfAbsent<span class=\"token punctuation\">)<\/span> p<span class=\"token punctuation\">.<\/span>val <span class=\"token operator\">&#061;<\/span> value<span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>binCount <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>binCount <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token constant\">TREEIFY_THRESHOLD<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token function\">treeifyBin<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u2466 \u6811\u5316\u5224\u5b9a<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>oldVal <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">return<\/span> oldVal<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u8bbe\u8ba1\u8981\u70b9\u9010\u6761\u8bf4\u6e05&#xff1a;<\/p>\n<table>\n<tr>\u8bbe\u8ba1\u70b9\u8bf4\u660e<\/tr>\n<tbody>\n<tr>\n<td>\u4e3a\u4ec0\u4e48\u9501\u6876\u5934\u800c\u4e0d\u662f\u9501\u6570\u7ec4<\/td>\n<td>\u6876\u5934\u662f\u6876\u5185\u94fe\u8868\u7684\u300c\u5165\u53e3\u300d&#xff0c;\u9501\u4f4f\u5b83 &#061; \u9501\u4f4f\u6574\u6761\u94fe\u7684\u5199\u5165\u53e3&#xff1b;\u4e0d\u540c\u6876\u7684\u5934\u8282\u70b9\u4e0d\u540c \u2192 \u4e92\u4e0d\u963b\u585e&#xff1b;\u9501\u5bf9\u8c61\u65e0\u9700\u81ea\u5efa&#xff0c;\u6bcf\u4e2a Node \u5929\u7136\u53ef\u5f53\u9501<\/td>\n<\/tr>\n<tr>\n<td>double-check \u7684\u610f\u4e49<\/td>\n<td>\u7b49\u9501\u671f\u95f4\u53ef\u80fd\u53d1\u751f\u6269\u5bb9&#xff08;\u672c\u6876\u88ab\u642c\u8d70\u5e76\u653e\u4e0a ForwardingNode&#xff09;&#xff0c;\u9192\u6765\u540e\u5fc5\u987b\u786e\u8ba4\u6876\u5934\u4ecd\u662f f&#xff0c;\u5426\u5219\u9501\u7684\u662f\u300c\u65e7\u4e16\u754c\u7684\u7a7a\u5934\u300d<\/td>\n<\/tr>\n<tr>\n<td>\u94fe\u8868\u63d2\u5165\u5728\u9501\u5185<\/td>\n<td>\u94fe\u8868\u5c3e\u63d2 &#043; \u8ba1\u6570\u90fd\u5fc5\u987b\u5728\u9501\u5185\u5b8c\u6210&#xff0c;\u4fdd\u8bc1\u540c\u6876\u5199\u5165\u4e32\u884c<\/td>\n<\/tr>\n<tr>\n<td>\u8986\u76d6\u4e0e\u8fd4\u56de<\/td>\n<td>put \u8fd4\u56de\u65e7\u503c&#xff1b;putIfAbsent&#xff08;onlyIfAbsent&#061;true&#xff09;\u5219\u53d1\u73b0\u5b58\u5728\u5c31\u8df3\u8fc7\u2014\u2014\u6ce8\u610f\u5b83\u62ff\u5230\u7684\u4e5f\u662f\u9501&#xff0c;\u6240\u4ee5\u662f\u539f\u5b50\u7684\u300c\u4e0d\u5b58\u5728\u624d\u5199\u300d<\/td>\n<\/tr>\n<tr>\n<td>TreeBin \u5206\u652f<\/td>\n<td>\u6811\u5316\u540e\u6876\u5934\u662f TreeBin&#xff0c;\u63d2\u5165\u6539\u8d70\u6811\u7b97\u6cd5&#xff0c;\u94fe\u8868\u8ba1\u6570\u76f4\u63a5\u8bb0 2&#xff08;\u907f\u514d\u6811\u5185\u8ba1\u6570&#xff09;<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4>4.4 \u6811\u5316\u89e6\u53d1<\/h4>\n<p>binCount \u2265 8 \u65f6\u8c03\u7528 treeifyBin&#xff0c;\u4f46\u5e76\u4e0d\u4e00\u5b9a\u771f\u7684\u6811\u5316&#xff1a;<\/p>\n<p><span class=\"token keyword\">private<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">treeifyBin<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> index<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> b<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">int<\/span> n<span class=\"token punctuation\">,<\/span> sc<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>tab <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;<\/span> tab<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token constant\">MIN_TREEIFY_CAPACITY<\/span><span class=\"token punctuation\">)<\/span>   <span class=\"token comment\">\/\/ \u2460 \u6876\u6570\u7ec4 &lt; 64<\/span><br \/>\n            <span class=\"token function\">tryPresize<\/span><span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>                        <span class=\"token comment\">\/\/    \u2192 \u5148\u6269\u5bb9\u5230 2n&#xff08;\u7a00\u91ca\u51b2\u7a81&#xff09;<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>b <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> index<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">&amp;&amp;<\/span> b<span class=\"token punctuation\">.<\/span>hash <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">synchronized<\/span> <span class=\"token punctuation\">(<\/span>b<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                         <span class=\"token comment\">\/\/ \u2461 \u9501\u6876\u5934&#xff0c;\u628a\u94fe\u8868\u5efa\u6210\u6811<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> index<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> b<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> hd <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span> tl <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> e <span class=\"token operator\">&#061;<\/span> b<span class=\"token punctuation\">;<\/span> e <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span> e <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span>next<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> p <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">(<\/span>e<span class=\"token punctuation\">.<\/span>hash<span class=\"token punctuation\">,<\/span> e<span class=\"token punctuation\">.<\/span>key<span class=\"token punctuation\">,<\/span> e<span class=\"token punctuation\">.<\/span>val<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>p<span class=\"token punctuation\">.<\/span>prev <span class=\"token operator\">&#061;<\/span> tl<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> hd <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u5148\u4e32\u6210\u53cc\u5411\u94fe\u8868<\/span><br \/>\n                        <span class=\"token keyword\">else<\/span> tl<span class=\"token punctuation\">.<\/span>next <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">;<\/span><br \/>\n                        tl <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><br \/>\n                    <span class=\"token function\">setTabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> index<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">TreeBin<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">(<\/span>hd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u6876\u5934\u6362\u6210 TreeBin(-2)<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5173\u952e\u8ba4\u77e5&#xff1a;\u6876\u6570\u7ec4\u4e0d\u8db3 64 \u65f6&#xff0c;hash \u51b2\u7a81\u518d\u4e25\u91cd\u4e5f\u4e0d\u6811\u5316&#xff0c;\u800c\u662f\u5148\u6269\u5bb9\u2014\u2014\u56e0\u4e3a\u6b64\u65f6\u6811\u5316\u7684\u6536\u76ca&#xff08;log n \u67e5\u627e&#xff09;\u654c\u4e0d\u8fc7\u300c\u6876\u592a\u5c11\u3001\u5bb9\u91cf\u9a6c\u4e0a\u8981\u7ffb\u500d\u300d\u7684\u6d6a\u8d39&#xff1b;\u6811\u5316\u662f\u300c\u6269\u5bb9\u4e5f\u6551\u4e0d\u4e86\u7684\u5355\u6876\u51b2\u7a81\u300d\u7684\u515c\u5e95\u3002<\/p>\n<h4>4.5 \u8ba1\u6570\u4e0e\u9608\u503c\u68c0\u67e5<\/h4>\n<p>putVal \u6536\u5c3e\u8c03\u7528 addCount(1L, binCount)&#xff0c;\u8ba1\u6570\u4e0e\u6269\u5bb9\u5728\u6b64\u8054\u52a8&#xff08;\u7b2c 5\u30016 \u7ae0\u8be6\u8ff0&#xff09;&#xff1a;<\/p>\n<p><span class=\"token keyword\">private<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">addCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">long<\/span> x<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> check<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">CounterCell<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> as<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">long<\/span> b<span class=\"token punctuation\">,<\/span> s<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>as <span class=\"token operator\">&#061;<\/span> counterCells<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span><br \/>\n        <span class=\"token operator\">!<\/span><span class=\"token class-name\">U<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">compareAndSwapLong<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">BASECOUNT<\/span><span class=\"token punctuation\">,<\/span> b <span class=\"token operator\">&#061;<\/span> baseCount<span class=\"token punctuation\">,<\/span> s <span class=\"token operator\">&#061;<\/span> b <span class=\"token operator\">&#043;<\/span> x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u7ade\u4e89\u6fc0\u70c8 \u2192 \u8d70 counterCells \u5206\u7247\u8ba1\u6570&#xff08;6.2&#xff09;<\/span><br \/>\n        <span class=\"token class-name\">CounterCell<\/span> a<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">long<\/span> v<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">int<\/span> m<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">boolean<\/span> uncontended <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>as <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span> <span class=\"token punctuation\">(<\/span>m <span class=\"token operator\">&#061;<\/span> as<span class=\"token punctuation\">.<\/span>length <span class=\"token operator\">&#8211;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">||<\/span><br \/>\n            <span class=\"token punctuation\">(<\/span>a <span class=\"token operator\">&#061;<\/span> as<span class=\"token punctuation\">[<\/span><span class=\"token class-name\">ThreadLocalRandom<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">getProbe<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&amp;<\/span> m<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span><br \/>\n            <span class=\"token operator\">!<\/span><span class=\"token punctuation\">(<\/span>uncontended <span class=\"token operator\">&#061;<\/span> <span class=\"token class-name\">U<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">compareAndSwapLong<\/span><span class=\"token punctuation\">(<\/span>a<span class=\"token punctuation\">,<\/span> <span class=\"token constant\">CELLVALUE<\/span><span class=\"token punctuation\">,<\/span> v <span class=\"token operator\">&#061;<\/span> a<span class=\"token punctuation\">.<\/span>value<span class=\"token punctuation\">,<\/span> v <span class=\"token operator\">&#043;<\/span> x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">fullAddCount<\/span><span class=\"token punctuation\">(<\/span>x<span class=\"token punctuation\">,<\/span> uncontended<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>       <span class=\"token comment\">\/\/ \u521d\u59cb\u5316\/\u6269\u5bb9\u5206\u7247\u6570\u7ec4<\/span><br \/>\n            <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span>                             <span class=\"token comment\">\/\/ \u8ba1\u6570\u8def\u5f84\u5728\u6b64\u7ed3\u675f<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>check <span class=\"token operator\">&lt;&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span>                 <span class=\"token comment\">\/\/ \u6876\u94fe\u5f88\u77ed&#xff0c;\u4e0d\u7528\u68c0\u67e5\u6269\u5bb9<\/span><br \/>\n        s <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">sumCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token comment\">\/\/ check \u2265 0 \u4e14\u5143\u7d20\u6570\u8d85\u9608\u503c \u2192 \u6269\u5bb9&#xff08;5.1&#xff09;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>check <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab<span class=\"token punctuation\">,<\/span> nt<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">int<\/span> n<span class=\"token punctuation\">,<\/span> sc<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>s <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">long<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span>sc <span class=\"token operator\">&#061;<\/span> sizeCtl<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token punctuation\">(<\/span>tab <span class=\"token operator\">&#061;<\/span> table<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n               <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;<\/span> tab<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token constant\">MAXIMUM_CAPACITY<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> rs <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">resizeStamp<\/span><span class=\"token punctuation\">(<\/span>n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>sc <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>sc <span class=\"token operator\">&gt;&gt;&gt;<\/span> <span class=\"token constant\">RESIZE_STAMP_SHIFT<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> rs <span class=\"token operator\">||<\/span> sc <span class=\"token operator\">&#061;&#061;<\/span> rs <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span> <span class=\"token operator\">||<\/span><br \/>\n                    sc <span class=\"token operator\">&#061;&#061;<\/span> rs <span class=\"token operator\">&#043;<\/span> <span class=\"token constant\">MAX_RESIZERS<\/span> <span class=\"token operator\">||<\/span> <span class=\"token punctuation\">(<\/span>nt <span class=\"token operator\">&#061;<\/span> nextTable<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span><br \/>\n                    transferIndex <span class=\"token operator\">&lt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><br \/>\n                    <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span>                      <span class=\"token comment\">\/\/ \u6269\u5bb9\u5df2\u5728\u8fdb\u884c\/\u5df2\u7ed3\u675f&#xff0c;\u8ba9\u4f4d<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">U<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">compareAndSwapInt<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">SIZECTL<\/span><span class=\"token punctuation\">,<\/span> sc<span class=\"token punctuation\">,<\/span> sc <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span>   <span class=\"token comment\">\/\/ \u767b\u8bb0\u300c\u6211\u6765\u5e2e\u5fd9\u300d<\/span><br \/>\n                    <span class=\"token function\">transfer<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> nt<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">U<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">compareAndSwapInt<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">SIZECTL<\/span><span class=\"token punctuation\">,<\/span> sc<span class=\"token punctuation\">,<\/span><br \/>\n                                         <span class=\"token punctuation\">(<\/span>rs <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token constant\">RESIZE_STAMP_SHIFT<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span>  <span class=\"token comment\">\/\/ \u6210\u4e3a\u7b2c\u4e00\u4e2a\u6269\u5bb9\u8005<\/span><br \/>\n                <span class=\"token function\">transfer<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            s <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">sumCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h4>4.6 put \u5168\u6d41\u7a0b\u51b3\u7b56\u56fe<\/h4>\n<p>  #mermaid-svg-IOXZnQiGl3ClkheL{font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;font-size:16px;fill:#333;}@keyframes edge-animation-frame{from{stroke-dashoffset:0;}}@keyframes dash{to{stroke-dashoffset:0;}}#mermaid-svg-IOXZnQiGl3ClkheL .edge-animation-slow{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 50s linear infinite;stroke-linecap:round;}#mermaid-svg-IOXZnQiGl3ClkheL .edge-animation-fast{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 20s linear infinite;stroke-linecap:round;}#mermaid-svg-IOXZnQiGl3ClkheL .error-icon{fill:#552222;}#mermaid-svg-IOXZnQiGl3ClkheL .error-text{fill:#552222;stroke:#552222;}#mermaid-svg-IOXZnQiGl3ClkheL .edge-thickness-normal{stroke-width:1px;}#mermaid-svg-IOXZnQiGl3ClkheL .edge-thickness-thick{stroke-width:3.5px;}#mermaid-svg-IOXZnQiGl3ClkheL .edge-pattern-solid{stroke-dasharray:0;}#mermaid-svg-IOXZnQiGl3ClkheL .edge-thickness-invisible{stroke-width:0;fill:none;}#mermaid-svg-IOXZnQiGl3ClkheL .edge-pattern-dashed{stroke-dasharray:3;}#mermaid-svg-IOXZnQiGl3ClkheL .edge-pattern-dotted{stroke-dasharray:2;}#mermaid-svg-IOXZnQiGl3ClkheL .marker{fill:#333333;stroke:#333333;}#mermaid-svg-IOXZnQiGl3ClkheL .marker.cross{stroke:#333333;}#mermaid-svg-IOXZnQiGl3ClkheL svg{font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;font-size:16px;}#mermaid-svg-IOXZnQiGl3ClkheL p{margin:0;}#mermaid-svg-IOXZnQiGl3ClkheL .label{font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;color:#333;}#mermaid-svg-IOXZnQiGl3ClkheL .cluster-label text{fill:#333;}#mermaid-svg-IOXZnQiGl3ClkheL .cluster-label span{color:#333;}#mermaid-svg-IOXZnQiGl3ClkheL .cluster-label span p{background-color:transparent;}#mermaid-svg-IOXZnQiGl3ClkheL .label text,#mermaid-svg-IOXZnQiGl3ClkheL span{fill:#333;color:#333;}#mermaid-svg-IOXZnQiGl3ClkheL .node rect,#mermaid-svg-IOXZnQiGl3ClkheL .node circle,#mermaid-svg-IOXZnQiGl3ClkheL .node ellipse,#mermaid-svg-IOXZnQiGl3ClkheL .node polygon,#mermaid-svg-IOXZnQiGl3ClkheL .node path{fill:#ECECFF;stroke:#9370DB;stroke-width:1px;}#mermaid-svg-IOXZnQiGl3ClkheL .rough-node .label text,#mermaid-svg-IOXZnQiGl3ClkheL .node .label text,#mermaid-svg-IOXZnQiGl3ClkheL .image-shape .label,#mermaid-svg-IOXZnQiGl3ClkheL .icon-shape .label{text-anchor:middle;}#mermaid-svg-IOXZnQiGl3ClkheL .node .katex path{fill:#000;stroke:#000;stroke-width:1px;}#mermaid-svg-IOXZnQiGl3ClkheL .rough-node .label,#mermaid-svg-IOXZnQiGl3ClkheL .node .label,#mermaid-svg-IOXZnQiGl3ClkheL .image-shape .label,#mermaid-svg-IOXZnQiGl3ClkheL .icon-shape .label{text-align:center;}#mermaid-svg-IOXZnQiGl3ClkheL .node.clickable{cursor:pointer;}#mermaid-svg-IOXZnQiGl3ClkheL .root .anchor path{fill:#333333!important;stroke-width:0;stroke:#333333;}#mermaid-svg-IOXZnQiGl3ClkheL .arrowheadPath{fill:#333333;}#mermaid-svg-IOXZnQiGl3ClkheL .edgePath .path{stroke:#333333;stroke-width:2.0px;}#mermaid-svg-IOXZnQiGl3ClkheL .flowchart-link{stroke:#333333;fill:none;}#mermaid-svg-IOXZnQiGl3ClkheL .edgeLabel{background-color:rgba(232,232,232, 0.8);text-align:center;}#mermaid-svg-IOXZnQiGl3ClkheL .edgeLabel p{background-color:rgba(232,232,232, 0.8);}#mermaid-svg-IOXZnQiGl3ClkheL .edgeLabel rect{opacity:0.5;background-color:rgba(232,232,232, 0.8);fill:rgba(232,232,232, 0.8);}#mermaid-svg-IOXZnQiGl3ClkheL .labelBkg{background-color:rgba(232, 232, 232, 0.5);}#mermaid-svg-IOXZnQiGl3ClkheL .cluster rect{fill:#ffffde;stroke:#aaaa33;stroke-width:1px;}#mermaid-svg-IOXZnQiGl3ClkheL .cluster text{fill:#333;}#mermaid-svg-IOXZnQiGl3ClkheL .cluster span{color:#333;}#mermaid-svg-IOXZnQiGl3ClkheL div.mermaidTooltip{position:absolute;text-align:center;max-width:200px;padding:2px;font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;font-size:12px;background:hsl(80, 100%, 96.2745098039%);border:1px solid #aaaa33;border-radius:2px;pointer-events:none;z-index:100;}#mermaid-svg-IOXZnQiGl3ClkheL .flowchartTitleText{text-anchor:middle;font-size:18px;fill:#333;}#mermaid-svg-IOXZnQiGl3ClkheL rect.text{fill:none;stroke-width:0;}#mermaid-svg-IOXZnQiGl3ClkheL .icon-shape,#mermaid-svg-IOXZnQiGl3ClkheL .image-shape{background-color:rgba(232,232,232, 0.8);text-align:center;}#mermaid-svg-IOXZnQiGl3ClkheL .icon-shape p,#mermaid-svg-IOXZnQiGl3ClkheL .image-shape p{background-color:rgba(232,232,232, 0.8);padding:2px;}#mermaid-svg-IOXZnQiGl3ClkheL .icon-shape .label rect,#mermaid-svg-IOXZnQiGl3ClkheL .image-shape .label rect{opacity:0.5;background-color:rgba(232,232,232, 0.8);fill:rgba(232,232,232, 0.8);}#mermaid-svg-IOXZnQiGl3ClkheL .label-icon{display:inline-block;height:1em;overflow:visible;vertical-align:-0.125em;}#mermaid-svg-IOXZnQiGl3ClkheL .node .label-icon path{fill:currentColor;stroke:revert;stroke-width:revert;}#mermaid-svg-IOXZnQiGl3ClkheL :root{&#8211;mermaid-font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;}<\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u6210\u529f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5931\u8d25 \u6709\u4eba\u62a2\u5148<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426 \u662f TreeBin<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u662f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5426<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>put key value<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>key \u6216 value \u4e3a null<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u629b NullPointerException<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>spread \u6270\u52a8\u54c8\u5e0c\u5b9a\u4f4d\u6876 i<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>table \u672a\u521d\u59cb\u5316<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>initTable \u62a2\u521d\u59cb\u5316\u6743<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6876 i \u4e3a\u7a7a<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>CAS \u653e\u5165\u65b0 Node<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u5b8c\u6210<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6876\u5934 hash &#061;&#061; MOVED<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>helpTransfer \u534f\u52a9\u6269\u5bb9<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>synchronized \u6876\u5934\u8282\u70b9<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6876\u5934\u662f\u666e\u901a Node<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u904d\u5386\u94fe\u8868<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u627e\u5230\u540c key<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u8986\u76d6 value<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u5c3e\u90e8\u63d2\u5165<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>putTreeVal \u6811\u5185\u63d2\u5165\u6216\u8986\u76d6<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u8bb0\u5f55 binCount<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>binCount \u2265 8<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>treeifyBin<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6876\u6570\u7ec4 \u2265 64<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u5148\u6269\u5bb9 2n<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u94fe\u8868\u8f6c\u7ea2\u9ed1\u6811<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>addCount \u8ba1\u6570<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u5143\u7d20\u6570\u8d85\u9608\u503c<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u89e6\u53d1\u6216\u52a0\u5165\u6269\u5bb9<\/p>\n<p><\/span><\/p>\n<hr \/>\n<h3>5. \u6269\u5bb9\u673a\u5236 transfer<\/h3>\n<p>\u6269\u5bb9\u662f CHM \u6e90\u7801\u91cc\u6700\u590d\u6742\u7684\u90e8\u5206&#xff0c;\u4e5f\u662f\u9762\u8bd5\u7684\u6df1\u6c34\u533a\u3002JDK 8 \u7684\u6269\u5bb9\u4e0e JDK 7 \u6700\u5927\u7684\u4e0d\u540c&#xff1a;\u5168\u8868\u6269\u5bb9 &#043; \u591a\u7ebf\u7a0b\u8ba4\u9886\u8fc1\u79fb\u3002<\/p>\n<h4>5.1 \u6269\u5bb9\u89e6\u53d1\u70b9<\/h4>\n<table>\n<tr>\u89e6\u53d1\u5165\u53e3\u573a\u666f<\/tr>\n<tbody>\n<tr>\n<td>addCount&#xff08;4.5&#xff09;<\/td>\n<td>\u6bcf\u6b21 put \u540e\u68c0\u67e5\u5143\u7d20\u6570 \u2265 sizeCtl \u9608\u503c<\/td>\n<\/tr>\n<tr>\n<td>tryPresize<\/td>\n<td>putAll\u3001treeifyBin \u9047\u6876\u6570\u7ec4 &lt; 64 \u65f6\u4e3b\u52a8\u6269<\/td>\n<\/tr>\n<tr>\n<td>helpTransfer<\/td>\n<td>\u5199\u5165\u65f6\u9047\u5230 MOVED \u6876\u5934&#xff0c;\u52a0\u5165\u6b63\u5728\u8fdb\u884c\u7684\u6269\u5bb9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u6269\u5bb9\u76ee\u6807 nextTable &#061; new Node[n &lt;&lt; 1]&#xff08;\u5bb9\u91cf\u7ffb\u500d&#xff0c;\u4ecd\u662f 2 \u7684\u5e42&#xff09;\u3002<\/p>\n<h4>5.2 \u591a\u7ebf\u7a0b\u5206\u5de5\u4e0e\u533a\u95f4\u9886\u53d6<\/h4>\n<p><span class=\"token keyword\">private<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">transfer<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> nextTab<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> n <span class=\"token operator\">&#061;<\/span> tab<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">,<\/span> stride<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u2460 \u6bcf\u4e2a\u7ebf\u7a0b\u6700\u5c11\u642c stride \u4e2a\u6876&#xff1a;\u5bb9\u91cf \/ 8 \/ CPU \u6838\u6570&#xff0c;\u4e0b\u9650 16<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>stride <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;&gt;&gt;<\/span> <span class=\"token number\">3<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">\/<\/span> <span class=\"token constant\">NCPU<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token constant\">MIN_TRANSFER_STRIDE<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        stride <span class=\"token operator\">&#061;<\/span> <span class=\"token constant\">MIN_TRANSFER_STRIDE<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>nextTab <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>              <span class=\"token comment\">\/\/ \u2461 \u7b2c\u4e00\u4e2a\u6269\u5bb9\u8005\u8d1f\u8d23\u5efa\u65b0\u8868<\/span><br \/>\n        <span class=\"token keyword\">try<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token annotation punctuation\">&#064;SuppressWarnings<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;unchecked&#034;<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> nt <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token operator\">?<\/span><span class=\"token punctuation\">,<\/span><span class=\"token operator\">?<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span>n <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            nextTab <span class=\"token operator\">&#061;<\/span> nt<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">catch<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Throwable<\/span> ex<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n        nextTable <span class=\"token operator\">&#061;<\/span> nextTab<span class=\"token punctuation\">;<\/span><br \/>\n        transferIndex <span class=\"token operator\">&#061;<\/span> n<span class=\"token punctuation\">;<\/span>              <span class=\"token comment\">\/\/ \u2462 \u8ba4\u9886\u6e38\u6807\u4ece\u6700\u540e\u4e00\u4e2a\u6876\u5f00\u59cb<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> nextn <span class=\"token operator\">&#061;<\/span> nextTab<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u2463 \u4e3b\u5faa\u73af&#xff1a;CAS \u9886\u53d6\u4e00\u6bb5\u533a\u95f4 [bound, i]&#xff0c;\u4ece\u9ad8\u5230\u4f4e\u8fc1\u79fb<\/span><br \/>\n    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span>advance <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span>         <span class=\"token comment\">\/\/ \u7b80\u5316\u793a\u610f<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> bound <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u9886\u53d6\u533a\u95f4&#xff1a;transferIndex \u662f\u5168\u5c40\u552f\u4e00\u6e38\u6807&#xff0c;<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u7ebf\u7a0b\u901a\u8fc7 CAS transferIndex -&#061; stride \u62ff\u8d70\u300c\u4ece transferIndex \u5f80\u524d\u7684\u4e00\u6bb5\u300d<\/span><br \/>\n        <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>i <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">||<\/span> i <span class=\"token operator\">&gt;&#061;<\/span> n <span class=\"token operator\">||<\/span> i <span class=\"token operator\">&#043;<\/span> n <span class=\"token operator\">&gt;&#061;<\/span> nextn<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> finish <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>f <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            advance <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">casTabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span> fwd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u7a7a\u6876\u76f4\u63a5\u653e ForwardingNode<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>fh <span class=\"token operator\">&#061;<\/span> f<span class=\"token punctuation\">.<\/span>hash<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token constant\">MOVED<\/span><span class=\"token punctuation\">)<\/span> advance <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u522b\u4eba\u642c\u5b8c\u4e86<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">synchronized<\/span> <span class=\"token punctuation\">(<\/span>f<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> \u8fc1\u79fb\u5355\u4e2a\u6876&#xff08;\u89c1 <span class=\"token number\">5.3<\/span>&#xff09;<span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5206\u5de5\u6a21\u578b&#xff08;\u52a1\u5fc5\u7406\u89e3\u300c\u6e38\u6807\u9886\u53d6\u300d\u800c\u4e0d\u662f\u300c\u5747\u5206\u300d&#xff09;&#xff1a;<\/p>\n<p>transferIndex \u521d\u59cb &#061; n&#xff08;\u65e7\u8868\u6876\u6570&#xff09;<br \/>\n                                \u250c\u2500 \u7ebf\u7a0b A \u8ba4\u9886 [n-16, n) \u8fd9\u6279\u6876 \u2500\u2510<br \/>\n        transferIndex \u2500\u2500CAS\u2500\u2500\u25b6  \u2502<br \/>\n   n \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524 \u7ebf\u7a0b B \u63a5\u7740\u8ba4\u9886 [n-32, n-16)<br \/>\n                                \u2502 \u7ebf\u7a0b C \u8ba4\u9886 [n-48, n-32)<br \/>\n                                \u25bc<br \/>\n  \u9ad8\u7d22\u5f15\u6876 \u2190\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 \u8fc1\u79fb\u65b9\u5411 \u2190\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500 \u4f4e\u7d22\u5f15\u6876<\/p>\n<ul>\n<li>\u6876\u6570\u5927\u4e8e stride \u00d7 \u7ebf\u7a0b\u6570 \u65f6\u6bcf\u4e2a\u7ebf\u7a0b\u642c\u4e00\u5757&#xff1b;\u6876\u5c11\u65f6\u4e00\u4e2a\u7ebf\u7a0b\u4e5f\u80fd\u642c\u5b8c&#xff1b;<\/li>\n<li>\u901f\u5ea6\u5feb\/\u540e\u6765\u7684\u7ebf\u7a0b\u53d1\u73b0 transferIndex \u2264 0&#xff08;\u6ca1\u6709\u5269\u4f59\u6876&#xff09;\u5c31\u9000\u51fa&#xff0c;\u518d\u5e2e finish&#xff1b;<\/li>\n<li>\u7a7a\u6876\u8fc1\u79fb\u96f6\u6210\u672c&#xff1a;\u76f4\u63a5 CAS \u653e\u4e00\u4e2a ForwardingNode \u5360\u4f4d&#xff0c;\u4e0d\u7528\u52a0\u9501\u3002<\/li>\n<\/ul>\n<h4>5.3 \u6876\u8fc1\u79fb\u4e0e\u9ad8\u4f4e\u4f4d\u62c6\u5206<\/h4>\n<p>\u5355\u4e2a\u6876\u7684\u8fc1\u79fb\u662f putVal \u7684\u955c\u50cf\u64cd\u4f5c&#xff1a;\u5148 synchronized(f) \u9501\u6876\u5934&#xff0c;\u518d\u51b3\u5b9a\u6876\u5185\u5143\u7d20\u53bb\u65b0\u8868\u7684\u54ea\u4e2a\u4f4d\u7f6e&#xff1a;<\/p>\n<p><span class=\"token keyword\">synchronized<\/span> <span class=\"token punctuation\">(<\/span>f<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> f<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> ln<span class=\"token punctuation\">,<\/span> hn<span class=\"token punctuation\">;<\/span>                    <span class=\"token comment\">\/\/ \u4f4e\u4f4d\u94fe \/ \u9ad8\u4f4d\u94fe<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fh <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                       <span class=\"token comment\">\/\/ \u666e\u901a\u94fe\u8868<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> runBit <span class=\"token operator\">&#061;<\/span> fh <span class=\"token operator\">&amp;<\/span> n<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u2460 \u5148\u627e\u5230\u300c\u6700\u540e\u4e00\u6bb5 runBit \u76f8\u540c\u7684\u5b50\u94fe\u300d&#xff0c;\u76f4\u63a5\u6574\u6bb5\u590d\u7528<\/span><br \/>\n            <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> lastRun <span class=\"token operator\">&#061;<\/span> f<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> p <span class=\"token operator\">&#061;<\/span> f<span class=\"token punctuation\">.<\/span>next<span class=\"token punctuation\">;<\/span> p <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span> p <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">.<\/span>next<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">int<\/span> b <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">.<\/span>hash <span class=\"token operator\">&amp;<\/span> n<span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>b <span class=\"token operator\">!&#061;<\/span> runBit<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> runBit <span class=\"token operator\">&#061;<\/span> b<span class=\"token punctuation\">;<\/span> lastRun <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>runBit <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> ln <span class=\"token operator\">&#061;<\/span> lastRun<span class=\"token punctuation\">;<\/span> hn <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span> hn <span class=\"token operator\">&#061;<\/span> lastRun<span class=\"token punctuation\">;<\/span> ln <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><\/p>\n<p>            <span class=\"token comment\">\/\/ \u2461 \u5176\u4f59\u8282\u70b9\u6309 (hash &amp; n) \u62c6\u6210\u9ad8\u4f4e\u4e24\u6761\u94fe<\/span><br \/>\n            <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> p <span class=\"token operator\">&#061;<\/span> f<span class=\"token punctuation\">;<\/span> p <span class=\"token operator\">!&#061;<\/span> lastRun<span class=\"token punctuation\">;<\/span> p <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">.<\/span>next<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">int<\/span> ph <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">.<\/span>hash<span class=\"token punctuation\">;<\/span> <span class=\"token class-name\">K<\/span> pk <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">.<\/span>key<span class=\"token punctuation\">;<\/span> <span class=\"token class-name\">V<\/span> pv <span class=\"token operator\">&#061;<\/span> p<span class=\"token punctuation\">.<\/span>val<span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>ph <span class=\"token operator\">&amp;<\/span> n<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> ln <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">(<\/span>ph<span class=\"token punctuation\">,<\/span> pk<span class=\"token punctuation\">,<\/span> pv<span class=\"token punctuation\">,<\/span> ln<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token keyword\">else<\/span>              hn <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">(<\/span>ph<span class=\"token punctuation\">,<\/span> pk<span class=\"token punctuation\">,<\/span> pv<span class=\"token punctuation\">,<\/span> hn<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token function\">setTabAt<\/span><span class=\"token punctuation\">(<\/span>nextTab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">,<\/span> ln<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>        <span class=\"token comment\">\/\/ \u2462 \u4f4e\u4f4d\u94fe \u2192 \u65b0\u8868\u539f\u4e0b\u6807 i<\/span><br \/>\n            <span class=\"token function\">setTabAt<\/span><span class=\"token punctuation\">(<\/span>nextTab<span class=\"token punctuation\">,<\/span> i <span class=\"token operator\">&#043;<\/span> n<span class=\"token punctuation\">,<\/span> hn<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>    <span class=\"token comment\">\/\/ \u2463 \u9ad8\u4f4d\u94fe \u2192 \u65b0\u8868\u4e0b\u6807 i&#043;n<\/span><br \/>\n            <span class=\"token function\">setTabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">,<\/span> fwd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>           <span class=\"token comment\">\/\/ \u2464 \u65e7\u6876\u653e ForwardingNode \u6536\u5de5<\/span><br \/>\n            advance <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>f <span class=\"token keyword\">instanceof<\/span> <span class=\"token class-name\">TreeBin<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u6811\u6876&#xff1a;\u904d\u5386\u53cc\u5411\u94fe\u8868\u540c\u6837\u62c6\u6210 lo\/hi \u4e24\u6761\u94fe&#xff0c;<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u82e5\u4efb\u4e00\u6761 \u2264 UNTREEIFY_THRESHOLD(6) \u5219\u9000\u5316\u6210\u666e\u901a Node \u94fe&#xff0c;<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u5426\u5219\u5404\u81ea new TreeBin \u4fdd\u6301\u6811\u7ed3\u6784<\/span><br \/>\n            <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4e3a\u4ec0\u4e48\u53ea\u770b hash &amp; n \u4e00\u4f4d\u5c31\u80fd\u62c6\u5206&#xff1f;\u56e0\u4e3a\u65e7\u8868\u957f\u5ea6 n \u662f 2 \u7684\u5e42&#xff1a;<\/p>\n<p>\u5173\u952e\u8ba4\u77e5&#xff08;\u6269\u5bb9\u6570\u5b66&#xff09;&#xff1a;\u6876\u4e0b\u6807 &#061; (n-1) &amp; hash\u3002\u6269\u5bb9\u5230 2n \u540e&#xff0c;\u65b0\u4e0b\u6807 &#061; (2n-1) &amp; hash &#061; \u539f\u4e0b\u6807 \u6216 \u539f\u4e0b\u6807 &#043; n\u2014\u2014\u591a\u51fa\u6765\u7684\u662f hash \u4e8c\u8fdb\u5236\u91cc\u7684\u7b2c log2(n) \u4f4d\u3002\u6240\u4ee5\u8fc1\u79fb\u53ea\u9700\u6309\u8fd9\u4e00\u4f4d\u628a\u4e00\u6761\u94fe\u62c6\u6210\u300c\u4f4e\u4f4d\u94fe ln\u300d\u548c\u300c\u9ad8\u4f4d\u94fe hn\u300d&#xff0c;\u5206\u522b\u653e\u5230\u65b0\u8868\u7684 i \u4e0e i&#043;n \u4e24\u4e2a\u6876&#xff0c;\u8282\u70b9\u5728\u65b0\u8868\u5185\u4e0d\u518d\u9700\u8981\u91cd\u65b0\u54c8\u5e0c&#xff08;\u8fd9\u4e5f\u662f HashMap \u540c\u6b3e\u4f18\u5316&#xff09;\u3002<\/p>\n<h4>5.4 ForwardingNode \u4e0e\u65e0\u9501\u8bfb<\/h4>\n<p>\u6269\u5bb9\u671f\u95f4\u65e7\u8868\u7684\u6bcf\u4e2a\u5df2\u8fc1\u79fb\u6876\u91cc\u90fd\u653e\u4e00\u4e2a ForwardingNode(-1)&#xff0c;\u5b83\u540c\u65f6\u627f\u62c5\u4e09\u4e2a\u804c\u8d23&#xff1a;<\/p>\n<table>\n<tr>\u804c\u8d23\u673a\u5236<\/tr>\n<tbody>\n<tr>\n<td>\u5199\u4fdd\u62a4<\/td>\n<td>\u5199\u7ebf\u7a0b\u5b9a\u4f4d\u5230\u8be5\u6876 \u2192 \u77e5\u9053\u6876\u5df2\u642c\u8d70 \u2192 helpTransfer \u52a0\u5165\u8fc1\u79fb&#xff0c;\u907f\u514d\u6570\u636e\u5199\u8fdb\u65e7\u6876\u4e22\u5931<\/td>\n<\/tr>\n<tr>\n<td>\u8bfb\u8f6c\u53d1<\/td>\n<td>\u8bfb\u7ebf\u7a0b get \u5230 MOVED \u6876 \u2192 \u987a\u7740 ForwardingNode \u91cc\u4fdd\u5b58\u7684 nextTable \u5f15\u7528\u53bb\u65b0\u8868\u627e&#xff08;\u89c1 7.1&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>\u8fc1\u79fb\u8fdb\u5ea6<\/td>\n<td>\u6876\u9010\u4e2a\u88ab\u66ff\u6362\u4e3a ForwardingNode&#xff0c;\u7b49\u4e8e\u53ef\u5e76\u884c\u7684\u8fc1\u79fb\u8fdb\u5ea6\u6761<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u6240\u6709\u6876\u642c\u5b8c\u540e\u7684\u6536\u5c3e&#xff08;\u6700\u540e\u4e00\u4e2a\u5b8c\u6210\u7684\u7ebf\u7a0b&#xff09;&#xff1a;<\/p>\n<p><span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>finish<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    nextTable <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span>                      <span class=\"token comment\">\/\/ \u65b0\u8868\u8f6c\u6b63<\/span><br \/>\n    table <span class=\"token operator\">&#061;<\/span> nextTab<span class=\"token punctuation\">;<\/span><br \/>\n    sizeCtl <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;&lt;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;&gt;&gt;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>        <span class=\"token comment\">\/\/ sizeCtl &#061; \u65b0\u5bb9\u91cf 2n \u7684 0.75 &#061; 1.5n<\/span><br \/>\n    <span class=\"token keyword\">return<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5173\u952e\u8ba4\u77e5&#xff1a;\u6269\u5bb9\u671f\u95f4\u8bfb\u7ebf\u7a0b\u6c38\u4e0d\u963b\u585e\u2014\u2014\u8981\u4e48\u8bfb\u65e7\u6876&#xff08;\u6ca1\u642c\u8d70&#xff09;&#xff0c;\u8981\u4e48\u7ecf ForwardingNode \u8f6c\u53d1\u5230\u65b0\u8868&#xff08;\u642c\u8d70\u4e86&#xff09;&#xff0c;\u65b0\u8868\u5185\u90e8\u5143\u7d20\u7684 next \u5f15\u7528\u94fe\u4e5f\u662f\u5b8c\u6574\u7684&#xff1b;\u6700\u591a\u770b\u5230\u300c\u65b0\u65e7\u4ea4\u66ff\u77ac\u95f4\u7684\u4e2d\u95f4\u72b6\u6001\u300d&#xff0c;\u8fd9\u5c31\u662f\u5f31\u4e00\u81f4\u6027\u3002\u4ee3\u4ef7\u662f&#xff1a;\u6269\u5bb9\u671f\u95f4 size() \u7b49\u7edf\u8ba1\u662f\u8fd1\u4f3c\u503c\u3002<\/p>\n<h3>6. \u8ba1\u6570\u673a\u5236<\/h3>\n<h4>6.1 CounterCell \u4e0e\u4f2a\u5171\u4eab<\/h4>\n<p>JDK 7 \u7684 size() \u8981\u628a\u5404\u6bb5 count \u52a0\u8d77\u6765&#xff0c;\u7ade\u4e89\u6fc0\u70c8\u65f6\u8fd8\u4e0d\u51c6&#xff1b;JDK 8 \u501f\u9274 LongAdder \u601d\u8def&#xff1a;\u4e00\u4e2a\u5168\u5c40 baseCount &#043; \u4e00\u7ec4\u5206\u7247 CounterCell[]&#xff0c;\u5199\u591a\u7ebf\u7a0b\u65f6\u5404\u81ea CAS \u81ea\u5df1\u7684\u5206\u7247&#xff0c;\u628a\u8ba1\u6570\u5668\u70ed\u70b9\u6253\u6563\u3002<\/p>\n<p><span class=\"token comment\">\/\/ \u6bcf\u4e2a\u5206\u7247\u4e00\u4e2a long&#xff0c;&#064;sun.misc.Contended \u6ce8\u89e3\u8ba9\u6bcf\u4e2a Cell \u72ec\u5360\u4e00\u4e2a\u7f13\u5b58\u884c&#xff08;128 \u5b57\u8282\u586b\u5145&#xff09;<\/span><br \/>\n<span class=\"token annotation punctuation\">&#064;sun.misc.Contended<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">CounterCell<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">volatile<\/span> <span class=\"token keyword\">long<\/span> value<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token class-name\">CounterCell<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">long<\/span> x<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> value <span class=\"token operator\">&#061;<\/span> x<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5173\u952e\u8ba4\u77e5&#xff1a;\u591a\u4e2a\u7ebf\u7a0b\u9891\u7e41\u5199\u4e0d\u540c Cell \u65f6&#xff0c;\u82e5\u5b83\u4eec\u843d\u5728\u540c\u4e00 CPU \u7f13\u5b58\u884c&#xff08;64 \u5b57\u8282&#xff09;&#xff0c;\u4f1a\u4e92\u76f8\u4f7f\u5bf9\u65b9\u7f13\u5b58\u5931\u6548&#xff08;\u4f2a\u5171\u4eab False Sharing&#xff09;&#xff0c;\u6027\u80fd\u65ad\u5d16\u3002&#064;Contended \u6ce8\u89e3\u5f3a\u5236 Cell \u4e4b\u95f4\u95f4\u9694\u4e00\u4e2a\u7f13\u5b58\u884c\u5927\u5c0f&#xff0c;\u4ece\u7269\u7406\u4e0a\u9694\u79bb\u70ed\u70b9\u3002<\/p>\n<h4>6.2 addCount \u4e0e fullAddCount<\/h4>\n<p>\u8ba1\u6570\u4e3b\u8def\u5f84&#xff08;\u6e90\u7801\u903b\u8f91\u89c1 4.5 \u8282\u4ee3\u7801&#xff09;&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ addCount(x, check) \u7684\u903b\u8f91&#xff1a;<\/span><br \/>\n<span class=\"token comment\">\/\/ \u2460 counterCells \u672a\u521d\u59cb\u5316 \u4e14 baseCount CAS \u6210\u529f \u2192 \u5b8c\u4e8b&#xff08;\u65e0\u7ade\u4e89\u5feb\u8def\u5f84&#xff09;<\/span><br \/>\n<span class=\"token comment\">\/\/ \u2461 \u5426\u5219\u6309\u7ebf\u7a0b\u63a2\u9488&#xff08;ThreadLocalRandom.getProbe&#xff09;\u54c8\u5e0c\u5230\u67d0\u4e2a Cell&#xff0c;CAS \u8be5 Cell<\/span><br \/>\n<span class=\"token comment\">\/\/ \u2462 \u8be5 Cell \u4e5f CAS \u5931\u8d25 \u2192 fullAddCount&#xff1a;\u6269\u5bb9 Cell \u6570\u7ec4&#xff08;\u7ffb\u500d&#xff09;\u6216\u6362\u4e2a Cell \u91cd\u8bd5<\/span><\/p>\n<p><span class=\"token comment\">\/\/ fullAddCount \u6838\u5fc3&#xff08;\u8282\u9009\u8bed\u4e49&#xff09;&#xff1a;\u521d\u59cb\u5316 counterCells \u7528 cellsBusy \u81ea\u65cb\u9501\u4fdd\u62a4<\/span><br \/>\n<span class=\"token keyword\">private<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">fullAddCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">long<\/span> x<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">boolean<\/span> wasUncontended<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> h<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>h <span class=\"token operator\">&#061;<\/span> <span class=\"token class-name\">ThreadLocalRandom<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">getProbe<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>   <span class=\"token comment\">\/\/ \u7ebf\u7a0b\u63a2\u9488 &#061; \u968f\u673a\u6570\u79cd\u5b50<\/span><br \/>\n        <span class=\"token class-name\">ThreadLocalRandom<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">localInit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        h <span class=\"token operator\">&#061;<\/span> <span class=\"token class-name\">ThreadLocalRandom<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">getProbe<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        wasUncontended <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">boolean<\/span> collide <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token class-name\">CounterCell<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> as<span class=\"token punctuation\">;<\/span> <span class=\"token class-name\">CounterCell<\/span> a<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">int<\/span> n<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">long<\/span> v<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>as <span class=\"token operator\">&#061;<\/span> counterCells<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;<\/span> as<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u968f\u673a\u9009\u4e2d\u4e00\u4e2a Cell&#xff0c;CAS \u7d2f\u52a0&#xff1b;\u5931\u8d25\u5219\u8003\u8651\u6269\u5bb9\u6570\u7ec4\u6216\u91cd\u54c8\u5e0c<\/span><br \/>\n            <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n            <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>cellsBusy <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token class-name\">U<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">compareAndSwapInt<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">CELLSBUSY<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token comment\">\/\/ \u62ff\u5230 cellsBusy \u9501 \u2192 counterCells \u7ffb\u500d\u6269\u5bb9<\/span><br \/>\n                <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>cellsBusy <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token class-name\">U<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">compareAndSwapInt<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">CELLSBUSY<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token comment\">\/\/ counterCells \u4e3a null&#xff1a;\u521d\u59cb\u5316 2 \u4e2a Cell<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h4>6.3 size \u4e0e mappingCount<\/h4>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">long<\/span> n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">sumCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0L<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">?<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">:<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token class-name\">Integer<\/span><span class=\"token punctuation\">.<\/span><span class=\"token constant\">MAX_VALUE<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">?<\/span> <span class=\"token class-name\">Integer<\/span><span class=\"token punctuation\">.<\/span><span class=\"token constant\">MAX_VALUE<\/span> <span class=\"token operator\">:<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span><span class=\"token punctuation\">)<\/span>n<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token keyword\">long<\/span> <span class=\"token function\">mappingCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>          <span class=\"token comment\">\/\/ JDK8 \u65b0\u589e&#xff1a;size \u6ea2\u51fa\u98ce\u9669\u7684\u6b63\u786e\u6253\u5f00\u65b9\u5f0f<\/span><br \/>\n    <span class=\"token keyword\">long<\/span> n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">sumCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0L<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">?<\/span> <span class=\"token number\">0L<\/span> <span class=\"token operator\">:<\/span> n<span class=\"token punctuation\">;<\/span>         <span class=\"token comment\">\/\/ \u9700\u8981\u7cbe\u786e\u503c\u8bf7\u914d sizeCtl\/\u9501\u573a\u666f\u81ea\u884c\u53d6\u820d<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">final<\/span> <span class=\"token keyword\">long<\/span> <span class=\"token function\">sumCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">CounterCell<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> as <span class=\"token operator\">&#061;<\/span> counterCells<span class=\"token punctuation\">;<\/span> <span class=\"token class-name\">CounterCell<\/span> a<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">long<\/span> sum <span class=\"token operator\">&#061;<\/span> baseCount<span class=\"token punctuation\">;<\/span>              <span class=\"token comment\">\/\/ \u57fa\u6570 &#043; \u6240\u6709\u5206\u7247<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>as <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> as<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>a <span class=\"token operator\">&#061;<\/span> as<span class=\"token punctuation\">[<\/span>i<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> sum <span class=\"token operator\">&#043;&#061;<\/span> a<span class=\"token punctuation\">.<\/span>value<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> sum<span class=\"token punctuation\">;<\/span>                        <span class=\"token comment\">\/\/ \u26a0\ufe0f \u904d\u5386\u671f\u95f4\u5e76\u53d1\u5199\u4ecd\u5728\u53d1\u751f \u2192 \u5f31\u4e00\u81f4\u8fd1\u4f3c\u503c<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4e00\u53e5\u8bdd\u6982\u62ec&#xff1a;size() \u4e0d\u505a\u4efb\u4f55\u52a0\u9501\u4e0e\u5feb\u7167&#xff0c;\u53ea\u662f\u300cbaseCount &#043; \u5404\u5206\u7247\u300d\u5feb\u901f\u6c42\u548c&#xff0c;\u8fd4\u56de\u7684\u662f\u67d0\u4e00\u77ac\u95f4\u7684\u8fd1\u4f3c\u503c&#xff1b;\u5143\u7d20\u6570\u53ef\u80fd\u8d85 int \u8303\u56f4\u65f6\u8bf7\u7528 mappingCount()&#xff08;\u8fd4\u56de long&#xff09;\u3002JDK \u6587\u6863\u660e\u786e\u8bf4\u4e86\u300c\u7528\u4e8e\u76d1\u63a7\u4e0e\u7edf\u8ba1&#xff0c;\u4e0d\u7528\u4e8e\u7cbe\u786e\u51b3\u7b56\u300d\u3002<\/p>\n<hr \/>\n<h3>7. \u8bfb\u64cd\u4f5c\u4e0e\u904d\u5386<\/h3>\n<h4>7.1 get \u4e3a\u4ec0\u4e48\u53ef\u4ee5\u65e0\u9501<\/h4>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token class-name\">V<\/span> <span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Object<\/span> key<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab<span class=\"token punctuation\">;<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> e<span class=\"token punctuation\">,<\/span> p<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">int<\/span> n<span class=\"token punctuation\">,<\/span> eh<span class=\"token punctuation\">;<\/span> <span class=\"token class-name\">K<\/span> ek<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> h <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">spread<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">.<\/span><span class=\"token function\">hashCode<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>tab <span class=\"token operator\">&#061;<\/span> table<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#061;<\/span> tab<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span> <span class=\"token operator\">&amp;&amp;<\/span><br \/>\n        <span class=\"token punctuation\">(<\/span>e <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&#8211;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&amp;<\/span> h<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>        <span class=\"token comment\">\/\/ \u2460 volatile \u8bfb\u6876\u5934<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>eh <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span>hash<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> h<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                       <span class=\"token comment\">\/\/ \u2461 \u6876\u5934\u5c31\u547d\u4e2d<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>ek <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span>key<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> key <span class=\"token operator\">||<\/span> <span class=\"token punctuation\">(<\/span>ek <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">&amp;&amp;<\/span> key<span class=\"token punctuation\">.<\/span><span class=\"token function\">equals<\/span><span class=\"token punctuation\">(<\/span>ek<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n                <span class=\"token keyword\">return<\/span> e<span class=\"token punctuation\">.<\/span>val<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>eh <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span>                                <span class=\"token comment\">\/\/ \u2462 hash&lt;0&#xff1a;\u7279\u6b8a\u8282\u70b9<\/span><br \/>\n            <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">(<\/span>p <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span><span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span>h<span class=\"token punctuation\">,<\/span> key<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">?<\/span> p<span class=\"token punctuation\">.<\/span>val <span class=\"token operator\">:<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>e <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span>next<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                  <span class=\"token comment\">\/\/ \u2463 \u94fe\u8868\u987a\u5e8f\u627e<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>e<span class=\"token punctuation\">.<\/span>hash <span class=\"token operator\">&#061;&#061;<\/span> h <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>ek <span class=\"token operator\">&#061;<\/span> e<span class=\"token punctuation\">.<\/span>key<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> key <span class=\"token operator\">||<\/span><br \/>\n                 <span class=\"token punctuation\">(<\/span>ek <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">&amp;&amp;<\/span> key<span class=\"token punctuation\">.<\/span><span class=\"token function\">equals<\/span><span class=\"token punctuation\">(<\/span>ek<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n                <span class=\"token keyword\">return<\/span> e<span class=\"token punctuation\">.<\/span>val<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u65e0\u9501\u8bfb\u7684\u5b89\u5168\u6027\u6765\u81ea\u4e09\u4e2a\u5c42\u6b21&#xff1a;<\/p>\n<table>\n<tr>\u5c42\u6b21\u4fdd\u8bc1<\/tr>\n<tbody>\n<tr>\n<td>tabAt volatile \u8bfb<\/td>\n<td>\u6876\u6570\u7ec4\u5143\u7d20\u8bfb\u53d6\u4e00\u5b9a\u770b\u5230\u300c\u6700\u8fd1\u7684\u53ef\u89c1\u72b6\u6001\u300d&#xff0c;\u6269\u5bb9\u6362\u8868\u540e\u8bfb\u5230\u7684\u662f\u65b0\u8868\u5f15\u7528<\/td>\n<\/tr>\n<tr>\n<td>\u94fe\u8868\u8282\u70b9\u7684 next \u662f volatile<\/td>\n<td>\u8fc1\u79fb\u4e2d\u7684\u94fe\u8868\u5728\u9501\u5185\u88ab\u300c\u590d\u5236\u300d\u5230\u65b0\u8868\u800c\u975e\u539f\u5730\u6539\u52a8&#xff08;5.3 \u7528 new Node \u91cd\u5efa&#xff09;&#xff0c;\u65e7\u94fe\u4e00\u65e6\u88ab\u8bfb\u7ebf\u7a0b\u5f15\u7528\u5c31\u4e0d\u4f1a\u88ab\u6539\u5199\u2014\u2014\u4e0d\u53d8\u6027&#xff1a;\u5df2\u53d1\u5e03\u7684\u94fe\u8868\u53ea\u8bfb\u4e0d\u5199<\/td>\n<\/tr>\n<tr>\n<td>\u7279\u6b8a\u8282\u70b9\u7684 find \u591a\u6001<\/td>\n<td>ForwardingNode \u2192 \u8f6c\u53d1\u65b0\u8868&#xff1b;TreeBin \u2192 \u6811\u67e5\u627e\u6216\u9000\u5316\u4e3a\u94fe\u8868\u626b\u63cf&#xff08;8.2&#xff09;<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u5173\u952e\u8ba4\u77e5&#xff1a;\u6269\u5bb9\u8fc1\u79fb\u662f\u300c\u590d\u5236\u5f0f\u300d\u800c\u975e\u300c\u79fb\u52a8\u5f0f\u300d\u2014\u2014\u65e7\u6876\u7684\u8282\u70b9\u94fe\u5728\u8fc1\u79fb\u65f6\u88ab\u65b0\u5efa\u6210\u4e24\u6761\u94fe\u653e\u8fdb\u65b0\u8868&#xff0c;\u65e7\u94fe\u8868\u7ed3\u6784\u4ece\u4e0d\u88ab\u539f\u5730\u4fee\u6539&#xff08;\u9664\u4e86\u6876\u5934\u6362\u6210 ForwardingNode \u8fd9\u4e00\u6b65 CAS&#xff09;\u3002\u6240\u4ee5\u8bfb\u7ebf\u7a0b\u65e0\u8bba\u62ff\u5230\u65e7\u8fd8\u662f\u65b0\u7ed3\u6784\u90fd\u5b89\u5168&#xff0c;\u8fd9\u5c31\u662f\u65e0\u9501\u8bfb\u7684\u6839\u57fa\u3002<\/p>\n<h4>7.2 remove \u4e0e replace<\/h4>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token class-name\">V<\/span> <span class=\"token function\">remove<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Object<\/span> key<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">return<\/span> <span class=\"token function\">replaceNode<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">final<\/span> <span class=\"token class-name\">V<\/span> <span class=\"token function\">replaceNode<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Object<\/span> key<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">V<\/span> value<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Object<\/span> cv<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> hash <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">spread<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">.<\/span><span class=\"token function\">hashCode<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab <span class=\"token operator\">&#061;<\/span> table<span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> f<span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">int<\/span> n<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">,<\/span> fh<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>tab <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token operator\">||<\/span> <span class=\"token punctuation\">(<\/span>f <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">(<\/span>n<span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token operator\">&amp;<\/span>hash<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span>                                  <span class=\"token comment\">\/\/ \u6876\u4e0d\u5b58\u5728 \u2192 \u65e0\u9700\u5220<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>fh <span class=\"token operator\">&#061;<\/span> f<span class=\"token punctuation\">.<\/span>hash<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token constant\">MOVED<\/span><span class=\"token punctuation\">)<\/span><br \/>\n            tab <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">helpTransfer<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> f<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>             <span class=\"token comment\">\/\/ \u6269\u5bb9\u4e2d\u5148\u5e2e\u5fd9<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">boolean<\/span> validated <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token keyword\">boolean<\/span> deleted <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">false<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">synchronized<\/span> <span class=\"token punctuation\">(<\/span>f<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                      <span class=\"token comment\">\/\/ \u540c\u6837\u9501\u6876\u5934<\/span><br \/>\n                <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">tabAt<\/span><span class=\"token punctuation\">(<\/span>tab<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;&#061;<\/span> f<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                    validated <span class=\"token operator\">&#061;<\/span> <span class=\"token boolean\">true<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fh <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>                  <span class=\"token comment\">\/\/ \u94fe\u8868\u5220\u9664&#xff1a;prev.next &#061; e.next<\/span><br \/>\n                        <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><br \/>\n                    <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>f <span class=\"token keyword\">instanceof<\/span> <span class=\"token class-name\">TreeBin<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                        <span class=\"token comment\">\/\/ \u6811\u5220\u9664&#xff1a;removeTreeNode&#xff08;\u4f1a\u7ef4\u62a4\u53cc\u5411\u94fe\u8868 &#043; \u7ea2\u9ed1\u6811\u5e73\u8861&#xff09;&#xff0c;<\/span><br \/>\n                        <span class=\"token comment\">\/\/ \u6876\u5185\u82e5\u53ea\u5269\u5c11\u91cf\u8282\u70b9\u4e0d\u4e3b\u52a8\u8f6c\u94fe\u8868&#xff08;\u7b49\u6269\u5bb9\u65f6\u518d\u9000\u5316&#xff09;<\/span><br \/>\n                    <span class=\"token punctuation\">}<\/span><br \/>\n                <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u5220\u9664\u6210\u529f \u2192 addCount(-1L, -1) \u56de\u9000\u8ba1\u6570<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>replace(key, oldValue, newValue) \u8d70\u540c\u4e00\u4e2a replaceNode(key, newValue, cv&#061;oldValue) \u91cd\u8f7d&#xff1a;\u5728\u9501\u5185\u6821\u9a8c\u65e7\u503c&#xff0c;\u5b9e\u73b0\u539f\u5b50\u7684\u6761\u4ef6\u66ff\u6362\u3002remove\/replace \u4e0e put \u5171\u7528\u540c\u4e00\u5957\u6876\u9501&#xff0c;\u6240\u4ee5\u300c\u8bfb-\u6539-\u5199\u300d\u7ec4\u5408&#xff08;\u5982 containsKey \u540e put&#xff09;\u4e4b\u95f4\u6ca1\u6709\u539f\u5b50\u6027\u2014\u2014\u9700\u8981\u539f\u5b50\u590d\u5408\u8bf7\u7528 7.4 \u7684 compute \u7cfb\u6216 putIfAbsent\u3002<\/p>\n<h4>7.3 \u5f31\u4e00\u81f4\u6027\u8fed\u4ee3\u5668<\/h4>\n<p>JDK 8 \u7684\u8fed\u4ee3\u5668&#xff08;KeyIterator\/ValueIterator\/EntryIterator&#xff09;\u57fa\u4e8e Traverser \u8bbe\u8ba1&#xff0c;\u904d\u5386\u89c4\u5219&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ \u8bed\u4e49&#xff1a;\u9010\u6876\u524d\u8fdb&#xff1b;\u9047\u5230 ForwardingNode \u5219\u987a\u7740 nextTable \u7ee7\u7eed\u627e\u8be5\u6876\u5728\u65b0\u8868\u7684\u4f4d\u7f6e<\/span><br \/>\n<span class=\"token comment\">\/\/ \u7279\u70b9&#xff1a;\u5168\u7a0b\u65e0\u9501\u3001\u4e0d\u629b ConcurrentModificationException\u3001\u904d\u5386\u671f\u95f4\u7684\u65b0\u589e\/\u5220\u9664&#034;\u90e8\u5206\u53ef\u89c1&#034;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Traverser<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab<span class=\"token punctuation\">;<\/span>        <span class=\"token comment\">\/\/ \u5f53\u524d\u6b63\u5728\u8bfb\u7684\u8868<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n    <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token function\">advance<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u6876\u5185\u8d70\u5b8c \u2192 \u4e0b\u4e00\u4e2a\u6876&#xff1b;\u6876\u5934\u662f ForwardingNode \u2192 \u8fdb\u5165 nextTable \u5bf9\u5e94\u6876\u7ee7\u7eed<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5f31\u4e00\u81f4\u6027\u7684\u5177\u4f53\u8868\u73b0&#xff1a;<\/p>\n<table>\n<tr>\u573a\u666f\u904d\u5386\u7ed3\u679c<\/tr>\n<tbody>\n<tr>\n<td>\u904d\u5386\u5f00\u59cb\u540e\u5176\u4ed6\u7ebf\u7a0b put \u65b0 key<\/td>\n<td>\u65b0\u5143\u7d20\u53ef\u80fd\u51fa\u73b0\u5728\u300c\u8fd8\u6ca1\u904d\u5386\u5230\u7684\u6876\u300d&#xff0c;\u4f1a\u88ab\u770b\u5230&#xff1b;\u5df2\u904d\u5386\u8fc7\u7684\u6876\u5219\u770b\u4e0d\u5230<\/td>\n<\/tr>\n<tr>\n<td>\u904d\u5386\u671f\u95f4\u5220\u9664\u5143\u7d20<\/td>\n<td>\u5df2\u88ab\u8fed\u4ee3\u5668\u6301\u5f15\u7528\u7684\u65e7\u8282\u70b9\u4ecd\u80fd\u8bfb\u5230&#xff08;\u4e0d\u629b\u5f02\u5e38&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>\u904d\u5386\u671f\u95f4\u6269\u5bb9<\/td>\n<td>\u8fed\u4ee3\u5668\u81ea\u52a8\u8ffd\u5230\u65b0\u8868\u7ee7\u7eed&#xff1b;\u53ef\u80fd\u8bfb\u5230\u540c\u4e00 key \u7684\u65b0\u65e7\u4e24\u4e2a\u503c&#xff08;\u65e7\u6876\u8282\u70b9\u88ab\u6301\u6709\u5f15\u7528\u65f6&#xff09;<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4e00\u53e5\u8bdd\u6982\u62ec&#xff1a;CHM \u8fed\u4ee3\u5668\u662f\u300c\u65e0\u9501 &#043; \u5c3d\u529b\u800c\u4e3a\u300d\u7684\u5feb\u7167&#xff0c;\u8fed\u4ee3\u671f\u95f4\u5bb9\u5668\u53ef\u5199\u3001\u4e0d\u629b CME&#xff0c;\u4f46\u4e0d\u4fdd\u8bc1\u770b\u5230\u8fed\u4ee3\u5f00\u59cb\u540e\u7684\u5168\u90e8\u53d8\u5316\u2014\u2014\u8fd9\u6b63\u662f\u4e3a\u4e86\u6027\u80fd\u4ed8\u51fa\u7684\u8bed\u4e49\u4ee3\u4ef7&#xff08;\u9002\u5408\u7edf\u8ba1\/\u62f7\u8d1d\/\u8f6c\u79fb\u7b49\u6279\u91cf\u64cd\u4f5c&#xff09;\u3002<\/p>\n<h4>7.4 \u590d\u5408\u64cd\u4f5c compute \u7cfb\u5217<\/h4>\n<p>computeIfAbsent \/ compute \/ merge \u90fd\u62ff\u5230\u6876\u9501\u540e\u6267\u884c&#xff0c;\u4fdd\u8bc1\u539f\u5b50\u6027&#xff1b;\u5176\u4e2d computeIfAbsent \u9700\u8981\u5360\u4f4d\u8282\u70b9\u9632\u6b62\u9012\u5f52\u8ba1\u7b97&#xff1a;<\/p>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token class-name\">V<\/span> <span class=\"token function\">computeIfAbsent<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">K<\/span> key<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Function<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token operator\">?<\/span> <span class=\"token keyword\">super<\/span> <span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">?<\/span> <span class=\"token keyword\">extends<\/span> <span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> mappingFunction<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> tab <span class=\"token operator\">&#061;<\/span> table<span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fh <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token constant\">RESERVED<\/span><span class=\"token punctuation\">)<\/span>               <span class=\"token comment\">\/\/ \u69fd\u4f4d\u88ab\u672c\u7ebf\u7a0b\u81ea\u5df1\u5360\u7740&#xff1f;<\/span><br \/>\n            <span class=\"token keyword\">throw<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">IllegalStateException<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;Recursive update&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ JDK9&#043;&#xff1a;\u9012\u5f52\u68c0\u6d4b<\/span><br \/>\n        <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u6ca1\u627e\u5230 \u2192 synchronized(f) \u5185\u5728\u6876\u5c3e\u63d2\u5165\u4e00\u4e2a ReservationNode(RESERVED) \u5360\u4f4d<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u91ca\u653e\u9501\u540e\u8c03\u7528 mappingFunction.apply(key) \u8ba1\u7b97&#xff08;\u6162\u64cd\u4f5c\u4e0d\u5728\u9501\u5185\u505a&#xff01;&#xff09;<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u7b97\u5b8c\u5e26\u7740\u7ed3\u679c\u518d\u56de\u6765\u628a\u5360\u4f4d\u8282\u70b9\u66ff\u6362\u6210\u771f\u5b9e\u8282\u70b9&#xff1b;\u7b97\u51fa\u6765 null \u5219\u5220\u9664\u5360\u4f4d<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4e24\u4e2a\u8bbe\u8ba1\u7ec6\u8282\u5f88\u503c\u94b1&#xff1a;<\/p>\n<li>\u8ba1\u7b97\u51fd\u6570\u5728\u9501\u5916\u6267\u884c&#xff1a;\u5360\u4f4d\u540e\u5148\u91ca\u653e\u9501\u518d\u8c03 mappingFunction&#xff0c;\u907f\u514d\u628a\u7528\u6237\u4ee3\u7801\u9501\u5728\u6876\u4e0a&#xff08;\u82e5\u5728\u9501\u5185\u8ba1\u7b97&#xff0c;\u7528\u6237\u51fd\u6570\u91cc\u518d\u78b0\u8fd9\u4e2a CHM \u5c31\u76f4\u63a5\u6b7b\u9501&#xff09;&#xff1b;<\/li>\n<li>\u9012\u5f52\u68c0\u6d4b&#xff1a;\u82e5\u7528\u6237\u51fd\u6570\u5185\u90e8\u53c8\u5bf9\u540c\u4e00\u4e2a key \u8c03 computeIfAbsent&#xff0c;\u4f1a\u53d1\u73b0\u5360\u4f4d\u8282\u70b9\u5e76\u629b IllegalStateException(&#034;Recursive update&#034;)\u2014\u2014\u26a0\ufe0f \u8fd9\u4e2a\u4fdd\u62a4\u662f JDK 9&#043; \u624d\u8865\u5168\u7684&#xff08;JDK-8160404\/8180352&#xff09;&#xff1a;JDK 8 \u7684 computeIfAbsent \u9047\u5230\u9012\u5f52\u66f4\u65b0\u4f1a\u6b7b\u5faa\u73af\u6216\u5185\u5b58\u6ea2\u51fa&#xff0c;\u7ecf\u5178\u7ebf\u4e0a\u4e8b\u6545&#xff08;\u5982 Spring \u65e9\u671f\u67d0\u4e9b\u5d4c\u5957\u7f13\u5b58\u52a0\u8f7d&#xff09;\u3002\u7ebf\u4e0a\u8dd1 JDK 8 \u7684\u540c\u5b66\u7559\u610f&#xff1a;computeIfAbsent \u7684\u56de\u8c03\u91cc\u4e0d\u8981\u518d\u67e5\u540c\u4e00\u4e2a key\u3002<\/li>\n<hr \/>\n<h3>8. \u6811\u5316\u4e0e TreeBin<\/h3>\n<h4>8.1 8 \u4e0e 6 \u4e24\u4e2a\u9608\u503c<\/h4>\n<table>\n<tr>\u9608\u503c\u503c\u89e6\u53d1\u65b9\u5411<\/tr>\n<tbody>\n<tr>\n<td>TREEIFY_THRESHOLD<\/td>\n<td>8<\/td>\n<td>\u6876\u5185\u94fe\u8868 \u2265 8 \u4e14\u6876\u6570\u7ec4 \u2265 64 \u2192 \u94fe\u8868\u8f6c\u7ea2\u9ed1\u6811<\/td>\n<\/tr>\n<tr>\n<td>UNTREEIFY_THRESHOLD<\/td>\n<td>6<\/td>\n<td>\u6269\u5bb9\u62c6\u6876\u540e&#xff0c;\u6811\u6876\u5185\u8282\u70b9 \u2264 6 \u2192 \u7ea2\u9ed1\u6811\u9000\u5316\u94fe\u8868<\/td>\n<\/tr>\n<tr>\n<td>MIN_TREEIFY_CAPACITY<\/td>\n<td>64<\/td>\n<td>\u6876\u6570\u7ec4\u957f\u5ea6\u4e0d\u8db3\u65f6\u5148\u6269\u5bb9\u4e0d\u6811\u5316<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4e3a\u4ec0\u4e48\u662f 8&#xff1f;\u5b98\u65b9\u6ce8\u91ca\u7ed9\u4e86\u4f9d\u636e\u2014\u2014\u6cca\u677e\u5206\u5e03&#xff1a;\u5728\u7406\u60f3\u968f\u673a\u54c8\u5e0c\u4e0b&#xff0c;\u5355\u4e2a\u6876\u5185\u8282\u70b9\u6570 k \u7684\u6982\u7387\u7ea6\u4e3a (0.5)^k \/ k!&#xff08;\u8d1f\u8f7d\u56e0\u5b50 0.75 \u65f6\u5230\u8fbe\u6b21\u6570 \u03bb\u22480.5&#xff09;&#xff1a;<\/p>\n<table>\n<tr>\u6876\u5185\u8282\u70b9\u6570 k\u6982\u7387<\/tr>\n<tbody>\n<tr>\n<td>8<\/td>\n<td>\u7ea6 0.00000006&#xff08;\u5343\u4e07\u5206\u4e4b\u516d&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>10<\/td>\n<td>\u7ea6 1.8e-13<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u94fe\u8868\u5230\u6811\u8981\u5230 8 \u624d\u89e6\u53d1&#xff0c;\u8bf4\u660e\u8fd9\u662f\u300c\u54c8\u5e0c\u5df2\u7ecf\u4e25\u91cd\u5931\u5b88&#xff08;\u6216\u6709\u4eba\u6076\u610f\u6784\u9020\u51b2\u7a81&#xff09;\u300d\u7684\u5f02\u5e38\u4fe1\u53f7&#xff1b;\u53cd\u8fc7\u6765\u9000\u5316\u9608\u503c\u53d6 6 \u800c\u975e 8&#xff0c;\u662f\u4e3a\u4e86\u907f\u514d\u5143\u7d20\u6570\u5728 7 \u9644\u8fd1\u9707\u8361\u65f6\u94fe\u8868\/\u6811\u53cd\u590d\u6a2a\u8df3&#xff08;8 \u4e0e 6 \u4e4b\u95f4\u7559\u4e86 1 \u7684\u6ede\u56de\u5e26&#xff09;\u3002\u8fd9\u4e24\u4e2a\u6570\u5b57\u540c\u65f6\u6697\u793a\u4e86&#xff1a;\u6b63\u5e38\u6570\u636e\u4e0b\u7ea2\u9ed1\u6811\u51e0\u4e4e\u4e0d\u4f1a\u51fa\u73b0&#xff0c;\u6811\u5316\u4e3b\u8981\u662f\u300c\u53cd\u54c8\u5e0c\u78b0\u649e\u653b\u51fb\u300d\u7684\u9632\u5fa1&#xff08;\u5982\u8ba9 HashMap \u9000\u5316\u6210\u94fe\u8868\u505a DoS&#xff09;\u3002<\/p>\n<h4>8.2 TreeBin \u7684\u8bfb\u5199\u9501\u601d\u8def<\/h4>\n<p>TreeBin \u672c\u8eab\u662f\u4e2a Node&#xff08;hash&#061;-2&#xff09;&#xff0c;\u5b83\u4f5c\u4e3a\u6876\u5934\u88ab put\/remove \u7684 synchronized \u9501\u4f4f&#xff08;\u5199\u4e92\u65a5\u5df2\u7531\u6876\u9501\u4fdd\u8bc1&#xff09;\u3002\u4f46 get \u662f\u65e0\u9501\u7684&#xff0c;\u5b83\u600e\u4e48\u5b89\u5168\u5730\u5e76\u53d1\u8bfb\u6811&#xff1f;\u7b54\u6848\u662f TreeBin \u5185\u90e8\u7684 lockState \u7b80\u5316\u8bfb\u5199\u9501&#xff1a;<\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">WRITER<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ bit0&#xff1a;\u5199\u8005\u9501&#xff08;\u6301\u6709\u8005 &#061; \u6811\u7ed3\u6784\u8c03\u6574\u65b9&#xff09;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">WAITER<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ bit1&#xff1a;\u6709\u5199\u8005\u5728\u7b49\u9501<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token constant\">READER<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">4<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ bit2&#043;&#xff1a;\u8bfb\u8005\u8ba1\u6570&#xff08;\u6bcf\u6b21 &#043;4&#xff09;<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u6811\u67e5\u627e&#xff08;get \u8def\u5f84&#xff09;\u2014\u2014\u5bf9\u8bfb\u8005\u53cb\u597d<\/span><br \/>\n<span class=\"token keyword\">final<\/span> <span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> <span class=\"token function\">find<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> h<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Object<\/span> k<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Node<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> e <span class=\"token operator\">&#061;<\/span> first<span class=\"token punctuation\">;<\/span> e <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> s<span class=\"token punctuation\">;<\/span> <span class=\"token class-name\">K<\/span> ek<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span>s <span class=\"token operator\">&#061;<\/span> lockState<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&amp;<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token constant\">WAITER<\/span> <span class=\"token operator\">|<\/span> <span class=\"token constant\">WRITER<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u2460 \u6709\u5199\u8005\u5728\u573a \u2192 \u76f4\u63a5\u6cbf first \u53cc\u5411\u94fe\u8868\u7ebf\u6027\u626b\u63cf&#xff08;\u7edd\u4e0d\u963b\u585e\u8bfb&#xff09;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">U<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">compareAndSwapInt<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token constant\">LOCKSTATE<\/span><span class=\"token punctuation\">,<\/span> s<span class=\"token punctuation\">,<\/span> s <span class=\"token operator\">&#043;<\/span> <span class=\"token constant\">READER<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token comment\">\/\/ \u2461 \u65e0\u5199\u8005 \u2192 CAS \u628a reader \u8ba1\u6570 &#043;1&#xff0c;\u7136\u540e\u653e\u5fc3\u8d70\u7ea2\u9ed1\u6811\u67e5\u627e<\/span><br \/>\n            <span class=\"token class-name\">TreeNode<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">K<\/span><span class=\"token punctuation\">,<\/span><span class=\"token class-name\">V<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> r<span class=\"token punctuation\">,<\/span> p<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token keyword\">return<\/span> p<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ finally \u4e2d CAS \u56de\u9000 reader \u8ba1\u6570<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token comment\">\/\/ CAS \u5931\u8d25&#xff08;\u4e0e\u5199\u8005\u7ade\u4e89\u77ac\u95f4&#xff09;\u2192 \u9000\u5316\u4e3a\u94fe\u8868\u626b\u63cf<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<table>\n<tr>\u64cd\u4f5c\u9501\u8bfb\u662f\u5426\u963b\u585e<\/tr>\n<tbody>\n<tr>\n<td>\u6876\u5934 put\/remove&#xff08;\u5148\u4e8e\u6811\u64cd\u4f5c&#xff09;<\/td>\n<td>synchronized(TreeBin)<\/td>\n<td>\u5199\u5199\u4e92\u65a5<\/td>\n<\/tr>\n<tr>\n<td>\u6811\u67e5\u627e get<\/td>\n<td>lockState \u8bfb\u8005\u8ba1\u6570&#xff08;CAS&#xff09;<\/td>\n<td>\u4e0d\u963b\u585e&#xff0c;\u6700\u574f\u7ebf\u6027\u626b\u63cf<\/td>\n<\/tr>\n<tr>\n<td>\u6811\u7ed3\u6784\u8c03\u6574&#xff08;\u5220\u9664\u8282\u70b9\u540e\u7684\u5e73\u8861&#xff09;<\/td>\n<td>lockRoot()&#xff1a;CAS lockState \u2192 WRITER<\/td>\n<td>\u8bfb\u7ebf\u7a0b\u4e0d\u9000\u8ba9\u5c31\u7f6e WAITER \u6807\u8bb0\u81ea\u65cb\/park \u7b49<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u6811\u7ef4\u62a4\u4e24\u4e2a\u7ed3\u6784&#xff1a;\u7ea2\u9ed1\u6811&#xff08;\u67e5&#xff09; &#043; first \u4e32\u8d77\u7684\u53cc\u5411\u94fe\u8868&#xff08;\u5199\u8005\u5728\u573a\u65f6\u7684\u515c\u5e95\u67e5 &#043; \u6269\u5bb9\u62c6\u6876\u7684\u904d\u5386\u4f9d\u636e&#xff09;\u2014\u2014\u53cc\u7ed3\u6784\u662f TreeBin \u4f18\u96c5\u5e76\u53d1\u8bfb\u7684\u57fa\u7840\u3002<\/p>\n<p>\u5173\u952e\u8ba4\u77e5&#xff1a;JDK 8 \u7684 CHM \u6811\u5316\u540e\u8bfb\u5199\u5e76\u53d1\u7b56\u7565\u662f\u300c\u8bfb\u8005\u7edd\u4e0d\u7b49\u5f85\u5199\u8005&#xff0c;\u5199\u8005\u5c3d\u91cf\u4e0d\u6253\u6270\u8bfb\u8005\u300d&#xff1a;\u6811\u5185\u67e5\u627e\u8d70 CAS \u8bfb\u8005\u8ba1\u6570&#xff1b;\u4e00\u6709\u5199\u8005&#xff08;\u5220\u9664\u540e\u5e73\u8861\u6811&#xff09;\u5728\u8bfb&#xff0c;\u65b0\u8bfb\u8005\u76f4\u63a5\u964d\u7ea7\u8d70\u94fe\u8868\u3002\u8fd9\u4e5f\u662f get \u5728\u6811\u6876\u4e0a\u4f9d\u65e7\u65e0\u9501\u7684\u539f\u56e0\u3002<\/p>\n<h4>8.3 \u6811\u4e0e\u94fe\u8868\u7684\u53cc\u5411\u8f6c\u6362<\/h4>\n<p>\u94fe\u8868 \u2500\u2500(\u6876\u5185\u8282\u70b9\u22658 \u4e14 table\u226564, \u9501\u6876\u5934)\u2500\u2500\u25b6  TreeBin(\u53cc\u5411\u94fe\u8868 \u2192 \u5e73\u8861\u6210\u7ea2\u9ed1\u6811)<br \/>\n TreeBin \u2500\u2500(\u6269\u5bb9\u62c6\u6876\u540e lo\/hi \u4efb\u4e00\u6761 \u22646)\u2500\u2500\u25b6  \u666e\u901a Node \u94fe\u8868<br \/>\n TreeBin \u2500\u2500(\u6876\u5185\u8282\u70b9\u4ecd\u591a)\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u25b6  \u4e24\u4e2a\u65b0 TreeBin \u5404\u8d70\u4e00\u8fb9<\/p>\n<ul>\n<li>\u94fe\u8868\u2192\u6811&#xff1a;4.4 \u7684 treeifyBin&#xff1a;\u5148\u5728\u9501\u5185\u628a Node \u94fe\u6539\u5efa\u6210 TreeNode \u53cc\u5411\u94fe\u8868&#xff0c;\u518d\u4ea4\u7ed9 TreeBin \u6784\u9020\u65f6\u505a\u7ea2\u9ed1\u6811\u5e73\u8861&#xff08;balanceInsertion&#xff09;&#xff1b;<\/li>\n<li>\u6811\u2192\u94fe\u8868&#xff1a;\u53ea\u53d1\u751f\u5728\u6269\u5bb9\u62c6\u6876&#xff08;5.3&#xff09;\u65f6\u2014\u2014\u62c6\u51fa\u7684\u9ad8\u4f4e\u4e24\u6761\u94fe\u82e5 \u22646 \u8282\u70b9&#xff0c;\u76f4\u63a5\u9000\u5316&#xff1b;\u6876\u5185\u5220\u9664&#xff08;removeTreeNode&#xff09;\u4e0d\u4e3b\u52a8\u9000\u5316&#xff0c;\u907f\u514d\u300c\u5220\u4e00\u4e2a\u5c31\u91cd\u6784\u300d&#xff1b;<\/li>\n<li>TreeNode \u7ee7\u627f Node \u4e14\u6301 prev \u6307\u9488&#xff0c;\u62c6\u6876\u65f6\u53ef\u4ee5\u50cf\u94fe\u8868\u4e00\u6837\u904d\u5386\u62c6\u5206&#xff0c;\u65e0\u9700\u5728\u6811\u4e0a\u505a split \u7b97\u6cd5\u3002<\/li>\n<\/ul>\n<hr \/>\n<h3>9. \u5173\u952e\u7c7b\u5173\u7cfb\u56fe<\/h3>\n<p>  #mermaid-svg-s4IneM1vkb6mLYx8{font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;font-size:16px;fill:#333;}@keyframes edge-animation-frame{from{stroke-dashoffset:0;}}@keyframes dash{to{stroke-dashoffset:0;}}#mermaid-svg-s4IneM1vkb6mLYx8 .edge-animation-slow{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 50s linear infinite;stroke-linecap:round;}#mermaid-svg-s4IneM1vkb6mLYx8 .edge-animation-fast{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 20s linear infinite;stroke-linecap:round;}#mermaid-svg-s4IneM1vkb6mLYx8 .error-icon{fill:#552222;}#mermaid-svg-s4IneM1vkb6mLYx8 .error-text{fill:#552222;stroke:#552222;}#mermaid-svg-s4IneM1vkb6mLYx8 .edge-thickness-normal{stroke-width:1px;}#mermaid-svg-s4IneM1vkb6mLYx8 .edge-thickness-thick{stroke-width:3.5px;}#mermaid-svg-s4IneM1vkb6mLYx8 .edge-pattern-solid{stroke-dasharray:0;}#mermaid-svg-s4IneM1vkb6mLYx8 .edge-thickness-invisible{stroke-width:0;fill:none;}#mermaid-svg-s4IneM1vkb6mLYx8 .edge-pattern-dashed{stroke-dasharray:3;}#mermaid-svg-s4IneM1vkb6mLYx8 .edge-pattern-dotted{stroke-dasharray:2;}#mermaid-svg-s4IneM1vkb6mLYx8 .marker{fill:#333333;stroke:#333333;}#mermaid-svg-s4IneM1vkb6mLYx8 .marker.cross{stroke:#333333;}#mermaid-svg-s4IneM1vkb6mLYx8 svg{font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;font-size:16px;}#mermaid-svg-s4IneM1vkb6mLYx8 p{margin:0;}#mermaid-svg-s4IneM1vkb6mLYx8 g.classGroup text{fill:#9370DB;stroke:none;font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;font-size:10px;}#mermaid-svg-s4IneM1vkb6mLYx8 g.classGroup text .title{font-weight:bolder;}#mermaid-svg-s4IneM1vkb6mLYx8 .cluster-label text{fill:#333;}#mermaid-svg-s4IneM1vkb6mLYx8 .cluster-label span{color:#333;}#mermaid-svg-s4IneM1vkb6mLYx8 .cluster-label span p{background-color:transparent;}#mermaid-svg-s4IneM1vkb6mLYx8 .cluster rect{fill:#ffffde;stroke:#aaaa33;stroke-width:1px;}#mermaid-svg-s4IneM1vkb6mLYx8 .cluster text{fill:#333;}#mermaid-svg-s4IneM1vkb6mLYx8 .cluster span{color:#333;}#mermaid-svg-s4IneM1vkb6mLYx8 .nodeLabel,#mermaid-svg-s4IneM1vkb6mLYx8 .edgeLabel{color:#131300;}#mermaid-svg-s4IneM1vkb6mLYx8 .edgeLabel .label rect{fill:#ECECFF;}#mermaid-svg-s4IneM1vkb6mLYx8 .label text{fill:#131300;}#mermaid-svg-s4IneM1vkb6mLYx8 .labelBkg{background:#ECECFF;}#mermaid-svg-s4IneM1vkb6mLYx8 .edgeLabel .label span{background:#ECECFF;}#mermaid-svg-s4IneM1vkb6mLYx8 .classTitle{font-weight:bolder;}#mermaid-svg-s4IneM1vkb6mLYx8 .node rect,#mermaid-svg-s4IneM1vkb6mLYx8 .node circle,#mermaid-svg-s4IneM1vkb6mLYx8 .node ellipse,#mermaid-svg-s4IneM1vkb6mLYx8 .node polygon,#mermaid-svg-s4IneM1vkb6mLYx8 .node path{fill:#ECECFF;stroke:#9370DB;stroke-width:1px;}#mermaid-svg-s4IneM1vkb6mLYx8 .divider{stroke:#9370DB;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 g.clickable{cursor:pointer;}#mermaid-svg-s4IneM1vkb6mLYx8 g.classGroup rect{fill:#ECECFF;stroke:#9370DB;}#mermaid-svg-s4IneM1vkb6mLYx8 g.classGroup line{stroke:#9370DB;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 .classLabel .box{stroke:none;stroke-width:0;fill:#ECECFF;opacity:0.5;}#mermaid-svg-s4IneM1vkb6mLYx8 .classLabel .label{fill:#9370DB;font-size:10px;}#mermaid-svg-s4IneM1vkb6mLYx8 .relation{stroke:#333333;stroke-width:1;fill:none;}#mermaid-svg-s4IneM1vkb6mLYx8 .dashed-line{stroke-dasharray:3;}#mermaid-svg-s4IneM1vkb6mLYx8 .dotted-line{stroke-dasharray:1 2;}#mermaid-svg-s4IneM1vkb6mLYx8 #compositionStart,#mermaid-svg-s4IneM1vkb6mLYx8 .composition{fill:#333333!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #compositionEnd,#mermaid-svg-s4IneM1vkb6mLYx8 .composition{fill:#333333!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #dependencyStart,#mermaid-svg-s4IneM1vkb6mLYx8 .dependency{fill:#333333!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #dependencyStart,#mermaid-svg-s4IneM1vkb6mLYx8 .dependency{fill:#333333!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #extensionStart,#mermaid-svg-s4IneM1vkb6mLYx8 .extension{fill:transparent!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #extensionEnd,#mermaid-svg-s4IneM1vkb6mLYx8 .extension{fill:transparent!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #aggregationStart,#mermaid-svg-s4IneM1vkb6mLYx8 .aggregation{fill:transparent!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #aggregationEnd,#mermaid-svg-s4IneM1vkb6mLYx8 .aggregation{fill:transparent!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #lollipopStart,#mermaid-svg-s4IneM1vkb6mLYx8 .lollipop{fill:#ECECFF!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 #lollipopEnd,#mermaid-svg-s4IneM1vkb6mLYx8 .lollipop{fill:#ECECFF!important;stroke:#333333!important;stroke-width:1;}#mermaid-svg-s4IneM1vkb6mLYx8 .edgeTerminals{font-size:11px;line-height:initial;}#mermaid-svg-s4IneM1vkb6mLYx8 .classTitleText{text-anchor:middle;font-size:18px;fill:#333;}#mermaid-svg-s4IneM1vkb6mLYx8 .label-icon{display:inline-block;height:1em;overflow:visible;vertical-align:-0.125em;}#mermaid-svg-s4IneM1vkb6mLYx8 .node .label-icon path{fill:currentColor;stroke:revert;stroke-width:revert;}#mermaid-svg-s4IneM1vkb6mLYx8 :root{&#8211;mermaid-font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;}<\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u7ee7\u627f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>table \u6876\u6570\u7ec4\u5143\u7d20<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u6876\u5185\u6811\u5bb9\u5668 hash&#061;-2<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u5206\u7247\u8ba1\u6570<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/p>\n<p>\u7ea2\u9ed1\u6811\u6839\u4e0e\u94fe\u8868<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>ConcurrentHashMap<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-table Node[]<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-nextTable Node[]<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-baseCount long<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-sizeCtl int<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-transferIndex int<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-counterCells CounterCell[]<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>&#043;put(key, value)<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>&#043;get(key)<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>&#043;remove(key)<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>&#043;size()<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>&#043;putIfAbsent(&#8230;)<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>Node<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>#hash int<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>#key K<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>#val V volatile<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>#next Node volatile<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>TreeNode<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-parent TreeNode<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-left TreeNode<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-right TreeNode<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-prev TreeNode \u53cc\u5411\u94fe\u8868<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-red boolean<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>TreeBin<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-root TreeNode<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-first TreeNode \u94fe\u5934<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-lockState int \u8bfb\u5199\u9501<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>&#043;putTreeVal(&#8230;)<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>&#043;find(h, k)<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>ForwardingNode<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-nextTable Node[]<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>&#043;find(h, k) : \u8f6c\u53d1\u5230\u65b0\u8868<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>ReservationNode<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>\u5360\u4f4d computeIfAbsent<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>CounterCell<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>-value long Contended<\/p>\n<p><\/span><\/p>\n<p>          <span class=\"nodeLabel markdown-node-label\"><\/p>\n<p>Map<\/p>\n<p><\/span><\/p>\n<p>\u8bfb\u56fe\u8981\u70b9&#xff1a;\u6240\u6709\u300c\u7279\u6b8a\u6876\u5934\u300d\u90fd\u662f Node \u7684\u5b50\u7c7b&#xff0c;table[i] \u8fd9\u4e00\u683c\u5b50\u91cc\u6c38\u8fdc\u653e Node\u2014\u2014put\/get\/remove \u62ff\u5230\u6876\u5934\u540e\u5148\u770b hash \u7b26\u53f7\u4e0e\u7c7b\u578b\u518d\u5206\u6d3e&#xff0c;\u8fd9\u662f\u7406\u89e3\u6574\u4efd\u6e90\u7801\u7684\u300c\u603b\u5f00\u5173\u300d&#xff1b;CounterCell \u4e0e\u4e3b\u8868\u65e0\u7ee7\u627f\u5173\u7cfb&#xff0c;\u53ea\u670d\u52a1\u4e8e\u8ba1\u6570\u3002<\/p>\n<h3>10. \u53ef\u8fd0\u884c\u793a\u4f8b<\/h3>\n<h4>10.1 \u5e76\u53d1\u8bfb\u5199\u4e0e\u904d\u5386 demo<\/h4>\n<p>\u6f14\u793a\u591a\u7ebf\u7a0b\u5199\u5165\u3001\u590d\u5408\u64cd\u4f5c\u4e0e\u5f31\u4e00\u81f4\u904d\u5386&#xff08;JDK 8&#043;&#xff0c;\u76f4\u63a5 javac\/java \u53ef\u8fd0\u884c&#xff09;&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ ChmConcurrentDemo.java<\/span><br \/>\n<span class=\"token keyword\">import<\/span> <span class=\"token import\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>util<span class=\"token punctuation\">.<\/span><\/span><span class=\"token class-name\">Map<\/span><\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">import<\/span> <span class=\"token import\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>util<span class=\"token punctuation\">.<\/span>concurrent<span class=\"token punctuation\">.<\/span><\/span><span class=\"token class-name\">ConcurrentHashMap<\/span><\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">import<\/span> <span class=\"token import\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>util<span class=\"token punctuation\">.<\/span>concurrent<span class=\"token punctuation\">.<\/span><\/span><span class=\"token class-name\">CountDownLatch<\/span><\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">import<\/span> <span class=\"token import\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>util<span class=\"token punctuation\">.<\/span>concurrent<span class=\"token punctuation\">.<\/span>atomic<span class=\"token punctuation\">.<\/span><\/span><span class=\"token class-name\">AtomicLong<\/span><\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">ChmConcurrentDemo<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">public<\/span> <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> args<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">throws<\/span> <span class=\"token class-name\">Exception<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">final<\/span> <span class=\"token class-name\">ConcurrentHashMap<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">String<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Integer<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> map <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">ConcurrentHashMap<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> threads <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">8<\/span><span class=\"token punctuation\">,<\/span> each <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">10_000<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">CountDownLatch<\/span> latch <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">CountDownLatch<\/span><span class=\"token punctuation\">(<\/span>threads<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ 8 \u4e2a\u7ebf\u7a0b\u5404\u5199\u5404\u7684 key \u533a\u95f4&#xff1a;\u51e0\u4e4e\u65e0\u6876\u51b2\u7a81 \u2192 \u5927\u90e8\u5206\u5199\u5165\u662f\u7a7a\u6876 CAS&#xff0c;\u96f6\u52a0\u9501<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> t <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> t <span class=\"token operator\">&lt;<\/span> threads<span class=\"token punctuation\">;<\/span> t<span class=\"token operator\">&#043;&#043;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> id <span class=\"token operator\">&#061;<\/span> t<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Thread<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">-&gt;<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> each<span class=\"token punctuation\">;<\/span> i<span class=\"token operator\">&#043;&#043;<\/span><span class=\"token punctuation\">)<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">put<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;k-&#034;<\/span> <span class=\"token operator\">&#043;<\/span> id <span class=\"token operator\">&#043;<\/span> <span class=\"token string\">&#034;-&#034;<\/span> <span class=\"token operator\">&#043;<\/span> i<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                latch<span class=\"token punctuation\">.<\/span><span class=\"token function\">countDown<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;writer-&#034;<\/span> <span class=\"token operator\">&#043;<\/span> t<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">start<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        latch<span class=\"token punctuation\">.<\/span><span class=\"token function\">await<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\u5199\u5165\u5b8c\u6210\u540e size        &#061; &#034;<\/span> <span class=\"token operator\">&#043;<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/\/ 80000<\/span><br \/>\n        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;mappingCount           &#061; &#034;<\/span> <span class=\"token operator\">&#043;<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">mappingCount<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u8bfb&#xff1a;\u65e0\u9501&#xff1b;key \u4e0d\u5b58\u5728\u8fd4\u56de null&#xff08;CHM \u672c\u8eab\u4e0d\u5141\u8bb8\u5b58 null&#xff0c;\u65e0\u4e8c\u4e49\u6027&#xff09;<\/span><br \/>\n        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;get \u4e0d\u5b58\u5728\u7684 key       &#061; &#034;<\/span> <span class=\"token operator\">&#043;<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;nope&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ putIfAbsent&#xff1a;\u5df2\u5b58\u5728\u5219\u8fd4\u56de\u65e7\u503c\u4e0d\u8986\u76d6&#xff08;\u539f\u5b50\u7684\u300c\u4e0d\u5b58\u5728\u624d\u5199\u300d&#xff09;<\/span><br \/>\n        <span class=\"token class-name\">Integer<\/span> old <span class=\"token operator\">&#061;<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">putIfAbsent<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;k-0-1&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;putIfAbsent \u8fd4\u56de\u65e7\u503c    &#061; &#034;<\/span> <span class=\"token operator\">&#043;<\/span> old<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>            <span class=\"token comment\">\/\/ 1<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ computeIfAbsent&#xff1a;mappingFunction \u53ea\u5bf9\u7f3a\u5e2d\u7684 key \u6267\u884c\u4e00\u6b21<\/span><br \/>\n        map<span class=\"token punctuation\">.<\/span><span class=\"token function\">computeIfAbsent<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;hot-key&#034;<\/span><span class=\"token punctuation\">,<\/span> k <span class=\"token operator\">-&gt;<\/span> k<span class=\"token punctuation\">.<\/span><span class=\"token function\">length<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">100<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        map<span class=\"token punctuation\">.<\/span><span class=\"token function\">computeIfAbsent<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;hot-key&#034;<\/span><span class=\"token punctuation\">,<\/span> k <span class=\"token operator\">-&gt;<\/span> k<span class=\"token punctuation\">.<\/span><span class=\"token function\">length<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">*<\/span> <span class=\"token number\">100<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;computeIfAbsent \u7ed3\u679c    &#061; &#034;<\/span> <span class=\"token operator\">&#043;<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;hot-key&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ 700<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u5f31\u4e00\u81f4\u6027\u8fed\u4ee3&#xff1a;\u904d\u5386\u671f\u95f4\u53e6\u4e00\u4e2a\u7ebf\u7a0b\u6301\u7eed\u5199\u5165 \u2192 \u4e0d\u629b CME<\/span><br \/>\n        <span class=\"token keyword\">final<\/span> <span class=\"token class-name\">AtomicLong<\/span> seen <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">AtomicLong<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">Thread<\/span> mutator <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Thread<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">-&gt;<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">100_000<\/span><span class=\"token punctuation\">;<\/span> i<span class=\"token operator\">&#043;&#043;<\/span><span class=\"token punctuation\">)<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">put<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;mut-&#034;<\/span> <span class=\"token operator\">&#043;<\/span> i<span class=\"token punctuation\">,<\/span> i<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        mutator<span class=\"token punctuation\">.<\/span><span class=\"token function\">start<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Map<span class=\"token punctuation\">.<\/span>Entry<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">String<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Integer<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> e <span class=\"token operator\">:<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">entrySet<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> seen<span class=\"token punctuation\">.<\/span><span class=\"token function\">incrementAndGet<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        mutator<span class=\"token punctuation\">.<\/span><span class=\"token function\">join<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\u8fed\u4ee3\u671f\u95f4\u770b\u5230\u7684\u6761\u76ee &gt;&#061; &#034;<\/span> <span class=\"token operator\">&#043;<\/span> seen<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>          <span class=\"token comment\">\/\/ \u4e0d\u4e00\u5b9a 80000&#043;&#xff0c;\u4e0d\u629b\u5f02\u5e38\u5373\u53ef<\/span><br \/>\n        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\u8fed\u4ee3\u7ed3\u675f\u540e size     &#061; &#034;<\/span> <span class=\"token operator\">&#043;<\/span> map<span class=\"token punctuation\">.<\/span><span class=\"token function\">size<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>$ javac ChmConcurrentDemo.java <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token function\">java<\/span> ChmConcurrentDemo<br \/>\n\u5199\u5165\u5b8c\u6210\u540e size        <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">80000<\/span><br \/>\nmappingCount           <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">80000<\/span><br \/>\nget \u4e0d\u5b58\u5728\u7684 key       <span class=\"token operator\">&#061;<\/span> null<br \/>\nputIfAbsent \u8fd4\u56de\u65e7\u503c    <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><br \/>\ncomputeIfAbsent \u7ed3\u679c    <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">700<\/span><br \/>\n\u8fed\u4ee3\u671f\u95f4\u770b\u5230\u7684\u6761\u76ee <span class=\"token operator\">&gt;&#061;<\/span> <span class=\"token number\">80000<\/span>   <span class=\"token comment\"># \u6570\u503c\u4e0d\u786e\u5b9a&#xff08;\u5f31\u4e00\u81f4&#xff09;&#xff0c;\u4f46\u4e0d\u629b ConcurrentModificationException<\/span><br \/>\n\u8fed\u4ee3\u7ed3\u675f\u540e size     <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">180000<\/span><\/p>\n<h4>10.2 \u7b80\u6613\u7f13\u5b58 demo<\/h4>\n<p>\u7528 CHM \u5b9e\u73b0\u7ebf\u7a0b\u5b89\u5168\u3001\u60f0\u6027\u8fc7\u671f\u3001\u5e76\u53d1\u52a0\u8f7d\u53ea\u6267\u884c\u4e00\u6b21\u7684\u672c\u5730\u7f13\u5b58&#xff08;\u6a21\u62df\u5e38\u89c1\u4e2d\u95f4\u4ef6\u7f13\u5b58\u5c42\u5199\u6cd5&#xff09;&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ SimpleCache.java<\/span><br \/>\n<span class=\"token keyword\">import<\/span> <span class=\"token import\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>util<span class=\"token punctuation\">.<\/span><\/span><span class=\"token class-name\">Map<\/span><\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">import<\/span> <span class=\"token import\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>util<span class=\"token punctuation\">.<\/span>concurrent<span class=\"token punctuation\">.<\/span><\/span><span class=\"token class-name\">ConcurrentHashMap<\/span><\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">import<\/span> <span class=\"token import\"><span class=\"token namespace\">java<span class=\"token punctuation\">.<\/span>util<span class=\"token punctuation\">.<\/span>function<span class=\"token punctuation\">.<\/span><\/span><span class=\"token class-name\">Function<\/span><\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">public<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">SimpleCache<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">private<\/span> <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Entry<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">final<\/span> <span class=\"token class-name\">Object<\/span> value<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">long<\/span> expireAt<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">Entry<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Object<\/span> value<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">long<\/span> ttlMillis<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">this<\/span><span class=\"token punctuation\">.<\/span>value <span class=\"token operator\">&#061;<\/span> value<span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">this<\/span><span class=\"token punctuation\">.<\/span>expireAt <span class=\"token operator\">&#061;<\/span> <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">currentTimeMillis<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#043;<\/span> ttlMillis<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">boolean<\/span> <span class=\"token function\">expired<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">return<\/span> <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">currentTimeMillis<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&gt;<\/span> expireAt<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">private<\/span> <span class=\"token keyword\">final<\/span> <span class=\"token class-name\">Map<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">String<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Entry<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> store <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">ConcurrentHashMap<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token punctuation\">&gt;<\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/** \u8bfb\u53d6&#xff1a;\u65e0\u9501 get &#043; \u60f0\u6027\u8fc7\u671f&#xff08;\u8fc7\u671f\u4e0d\u4e3b\u52a8\u6e05\u7406&#xff0c;\u8bfb\u5230\u624d\u4e22\u5f03&#xff09; *\/<\/span><br \/>\n    <span class=\"token keyword\">public<\/span> <span class=\"token class-name\">Object<\/span> <span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span> key<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token class-name\">Entry<\/span> e <span class=\"token operator\">&#061;<\/span> store<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token punctuation\">(<\/span>e <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">||<\/span> e<span class=\"token punctuation\">.<\/span><span class=\"token function\">expired<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">?<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">:<\/span> e<span class=\"token punctuation\">.<\/span>value<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/** \u5199\u5165&#xff1a;\u5e26 TTL \u7684 put *\/<\/span><br \/>\n    <span class=\"token keyword\">public<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">put<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span> key<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Object<\/span> value<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">long<\/span> ttlMillis<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        store<span class=\"token punctuation\">.<\/span><span class=\"token function\">put<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Entry<\/span><span class=\"token punctuation\">(<\/span>value<span class=\"token punctuation\">,<\/span> ttlMillis<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/** \u7f13\u5b58\u52a0\u8f7d\u5668&#xff1a;\u591a\u7ebf\u7a0b\u540c\u65f6 miss \u540c\u4e00 key \u65f6&#xff0c;loader \u53ea\u6267\u884c\u4e00\u6b21&#xff08;computeIfAbsent \u8bed\u4e49&#xff09; *\/<\/span><br \/>\n    <span class=\"token keyword\">public<\/span> <span class=\"token class-name\">Object<\/span> <span class=\"token function\">getOrLoad<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span> key<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">long<\/span> ttlMillis<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Function<\/span><span class=\"token generics\"><span class=\"token punctuation\">&lt;<\/span><span class=\"token class-name\">String<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">Object<\/span><span class=\"token punctuation\">&gt;<\/span><\/span> loader<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token class-name\">Object<\/span> hit <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>hit <span class=\"token operator\">!&#061;<\/span> <span class=\"token keyword\">null<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">return<\/span> hit<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u8fd4\u56de null \u8868\u793a\u4e0d\u7f13\u5b58\u8be5 key&#xff1b;mappingFunction \u5728\u6876\u9501\u4fdd\u62a4\u4e0b\u53ea\u6267\u884c\u4e00\u6b21<\/span><br \/>\n        <span class=\"token class-name\">Entry<\/span> loaded <span class=\"token operator\">&#061;<\/span> store<span class=\"token punctuation\">.<\/span><span class=\"token function\">computeIfAbsent<\/span><span class=\"token punctuation\">(<\/span>key<span class=\"token punctuation\">,<\/span><br \/>\n                k <span class=\"token operator\">-&gt;<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token class-name\">Object<\/span> v <span class=\"token operator\">&#061;<\/span> loader<span class=\"token punctuation\">.<\/span><span class=\"token function\">apply<\/span><span class=\"token punctuation\">(<\/span>k<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                       <span class=\"token keyword\">return<\/span> v <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">?<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">:<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Entry<\/span><span class=\"token punctuation\">(<\/span>v<span class=\"token punctuation\">,<\/span> ttlMillis<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> loaded <span class=\"token operator\">&#061;&#061;<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">?<\/span> <span class=\"token keyword\">null<\/span> <span class=\"token operator\">:<\/span> loaded<span class=\"token punctuation\">.<\/span>value<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">public<\/span> <span class=\"token keyword\">static<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token class-name\">String<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> args<span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">throws<\/span> <span class=\"token class-name\">Exception<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token class-name\">SimpleCache<\/span> cache <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">SimpleCache<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">Thread<\/span><span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span> ts <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Thread<\/span><span class=\"token punctuation\">[<\/span><span class=\"token number\">10<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> t <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> t <span class=\"token operator\">&lt;<\/span> ts<span class=\"token punctuation\">.<\/span>length<span class=\"token punctuation\">;<\/span> t<span class=\"token operator\">&#043;&#043;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">final<\/span> <span class=\"token keyword\">int<\/span> id <span class=\"token operator\">&#061;<\/span> t<span class=\"token punctuation\">;<\/span><br \/>\n            ts<span class=\"token punctuation\">[<\/span>t<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token class-name\">Thread<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">-&gt;<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token comment\">\/\/ 10 \u4e2a\u7ebf\u7a0b\u540c\u65f6\u6253\u540c\u4e00\u4e2a key&#xff1a;\u671f\u671b [loader] \u53ea\u6253\u5370\u4e00\u6b21<\/span><br \/>\n                <span class=\"token class-name\">Object<\/span> v <span class=\"token operator\">&#061;<\/span> cache<span class=\"token punctuation\">.<\/span><span class=\"token function\">getOrLoad<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;user:10086&#034;<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">5_000<\/span><span class=\"token punctuation\">,<\/span><br \/>\n                        k <span class=\"token operator\">-&gt;<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;  [loader] \u52a0\u8f7d &#034;<\/span> <span class=\"token operator\">&#043;<\/span> k<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                               <span class=\"token keyword\">return<\/span> <span class=\"token string\">&#034;value-of-&#034;<\/span> <span class=\"token operator\">&#043;<\/span> k<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\u7ebf\u7a0b &#034;<\/span> <span class=\"token operator\">&#043;<\/span> id <span class=\"token operator\">&#043;<\/span> <span class=\"token string\">&#034; \u62ff\u5230 &#034;<\/span> <span class=\"token operator\">&#043;<\/span> v<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            ts<span class=\"token punctuation\">[<\/span>t<span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">start<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token class-name\">Thread<\/span> t <span class=\"token operator\">:<\/span> ts<span class=\"token punctuation\">)<\/span> t<span class=\"token punctuation\">.<\/span><span class=\"token function\">join<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;TTL \u5185\u76f4\u63a5\u547d\u4e2d: &#034;<\/span> <span class=\"token operator\">&#043;<\/span> cache<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;user:10086&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token class-name\">Thread<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">sleep<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">5_200<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>                       <span class=\"token comment\">\/\/ \u7b49 TTL(5s) \u8fc7\u671f<\/span><br \/>\n        <span class=\"token class-name\">System<\/span><span class=\"token punctuation\">.<\/span>out<span class=\"token punctuation\">.<\/span><span class=\"token function\">println<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;TTL \u8fc7\u671f\u540e\u518d\u8bfb: &#034;<\/span> <span class=\"token operator\">&#043;<\/span> cache<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;user:10086&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ null<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>$ javac SimpleCache.java <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token function\">java<\/span> SimpleCache<br \/>\n  <span class=\"token punctuation\">[<\/span>loader<span class=\"token punctuation\">]<\/span> \u52a0\u8f7d user:10086          <span class=\"token comment\"># \u53ea\u51fa\u73b0\u4e00\u6b21 \u2192 \u52a0\u8f7d\u903b\u8f91\u53ea\u6267\u884c\u4e86\u4e00\u6b21<\/span><br \/>\n\u7ebf\u7a0b <span class=\"token number\">0<\/span> \u62ff\u5230 value-of-user:10086<br \/>\n\u7ebf\u7a0b <span class=\"token number\">1<\/span> \u62ff\u5230 value-of-user:10086<br \/>\n<span class=\"token punctuation\">..<\/span>.&#xff08;10 \u884c&#xff0c;\u503c\u76f8\u540c&#xff09;<br \/>\nTTL \u5185\u76f4\u63a5\u547d\u4e2d: value-of-user:10086<br \/>\nTTL \u8fc7\u671f\u540e\u518d\u8bfb: null<\/p>\n<p>\u26a0\ufe0f \u6269\u5c55\u601d\u8003&#xff1a;\u4e0a\u8ff0 getOrLoad \u5b58\u5728\u300c\u8bfb\u5230\u4e86\u521a\u8fc7\u671f\u4f46\u5c1a\u672a\u88ab\u66ff\u6362\u7684 Entry\u300d\u7684\u6781\u5c0f\u7a97\u53e3&#xff08;\u5148 get \u540e computeIfAbsent \u4e0d\u662f\u539f\u5b50\u64cd\u4f5c&#xff09;\u2014\u2014\u751f\u4ea7\u7ea7\u7f13\u5b58\u8bf7\u7528 compute \u7cfb\u5217\u5728\u9501\u5185\u5b8c\u6210\u8fc7\u671f\u5224\u65ad&#xff0c;\u6216\u7528 Caffeine\/Guava Cache \u8fd9\u79cd\u6210\u719f\u5b9e\u73b0\u3002<\/p>\n<hr \/>\n<h3>11. \u6a2a\u5411\u5bf9\u6bd4\u603b\u8868<\/h3>\n<table>\n<tr>\u7ef4\u5ea6HashtableCollections.synchronizedMapCHM JDK 7CHM JDK 8&#043;HashMap&#xff08;\u7ebf\u7a0b\u79c1\u6709&#xff09;<\/tr>\n<tbody>\n<tr>\n<td>\u9501\u7c92\u5ea6<\/td>\n<td>\u6574\u8868<\/td>\n<td>\u6574\u8868<\/td>\n<td>16 \u5206\u6bb5<\/td>\n<td>\u5355\u6876&#xff08;\u51b2\u7a81\u65f6&#xff09;<\/td>\n<td>\u65e0<\/td>\n<\/tr>\n<tr>\n<td>\u65e0\u51b2\u7a81\u5199\u5165<\/td>\n<td>\u5168\u7a0b\u9501<\/td>\n<td>\u5168\u7a0b\u9501<\/td>\n<td>\u9501\u5206\u6bb5<\/td>\n<td>\u4e00\u6b21 CAS<\/td>\n<td>CAS \u90fd\u4e0d\u7528&#xff08;\u5355\u7ebf\u7a0b&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>\u8bfb<\/td>\n<td>\u9501<\/td>\n<td>\u9501<\/td>\n<td>\u65e0\u9501&#xff08;volatile&#xff09;<\/td>\n<td>\u65e0\u9501<\/td>\n<td>\u65e0\u9501<\/td>\n<\/tr>\n<tr>\n<td>\u6269\u5bb9<\/td>\n<td>\u5168\u8868\u9501\u540e\u642c<\/td>\n<td>\u5168\u8868\u9501\u540e\u642c<\/td>\n<td>\u6bb5\u5185\u642c<\/td>\n<td>\u591a\u7ebf\u7a0b\u534f\u4f5c\u642c<\/td>\n<td>\u5355\u7ebf\u7a0b\u642c<\/td>\n<\/tr>\n<tr>\n<td>\u8ba1\u6570<\/td>\n<td>size \u53d8\u91cf<\/td>\n<td>\u2014<\/td>\n<td>\u6bb5 count \u548c<\/td>\n<td>CounterCell \u5206\u7247<\/td>\n<td>modCount&#043;size<\/td>\n<\/tr>\n<tr>\n<td>null<\/td>\n<td>\u4e0d\u5141\u8bb8<\/td>\n<td>\u53d6\u51b3\u4e8e\u5305\u88c5\u7684 Map<\/td>\n<td>\u4e0d\u5141\u8bb8<\/td>\n<td>\u4e0d\u5141\u8bb8<\/td>\n<td>key\/value \u5747\u53ef<\/td>\n<\/tr>\n<tr>\n<td>\u8fed\u4ee3<\/td>\n<td>fail-fast<\/td>\n<td>fail-fast<\/td>\n<td>\u5f31\u4e00\u81f4<\/td>\n<td>\u5f31\u4e00\u81f4<\/td>\n<td>fail-fast<\/td>\n<\/tr>\n<tr>\n<td>\u9002\u7528<\/td>\n<td>\u9057\u7559\u4ee3\u7801<\/td>\n<td>\u5feb\u901f\u5c0f\u89c4\u6a21\u5305\u88c5<\/td>\n<td>\u5df2\u88ab 8 \u53d6\u4ee3<\/td>\n<td>\u9ed8\u8ba4\u9009\u62e9<\/td>\n<td>\u65e0\u7ebf\u7a0b\u5171\u4eab<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u51b3\u7b56\u5efa\u8bae&#xff1a;<\/p>\n<li>\u65e0\u5e76\u53d1\u5171\u4eab \u2192 HashMap&#xff1b;<\/li>\n<li>\u591a\u7ebf\u7a0b\u5171\u4eab\u3001\u9700\u8981\u5e76\u53d1\u8bfb\u5199 \u2192 ConcurrentHashMap&#xff08;JDK 8&#043;&#xff09;&#xff1b;<\/li>\n<li>\u9700\u8981\u6709\u5e8f\/\u8303\u56f4\u67e5\u8be2 \u2192 ConcurrentSkipListMap&#xff1b;<\/li>\n<li>Hashtable \/ synchronizedMap \u53ea\u51fa\u73b0\u5728\u300c\u65e0\u6cd5\u6539\u4ee3\u7801\u300d\u7684\u9057\u7559\u573a\u666f\u3002<\/li>\n<hr \/>\n<h3>12. FAQ \u4e0e\u6269\u5c55\u70b9<\/h3>\n<p>Q1&#xff1a;\u4e3a\u4ec0\u4e48 JDK 8 \u653e\u5f03\u5206\u6bb5\u9501&#xff0c;\u6539\u7528 CAS &#043; synchronized \u9501\u6876\u5934&#xff1f;<\/p>\n<p>\u89c1 1.3 \u7684\u4e09\u6761\u539f\u56e0&#xff0c;\u6d53\u7f29\u4e3a\u4e00\u53e5&#xff1a;\u5206\u6bb5\u9501\u628a\u5e76\u53d1\u5ea6\u9501\u6b7b\u5728 16&#xff0c;\u4e14\u65e0\u8bba\u51b2\u7a81\u4e0e\u5426\u5199\u5165\u90fd\u8981\u78b0\u9501&#xff1b;\u6876\u9501\u7c92\u5ea6\u7ec6\u5230\u300c\u6876\u6570\u300d\u3001\u65e0\u51b2\u7a81\u5199\u5165\u9000\u5316\u4e3a CAS\u3001\u8bfb\u5b8c\u5168\u65e0\u9501&#xff0c;\u52a0\u4e0a JDK 6 \u540e synchronized \u5df2\u88ab JVM \u6df1\u5ea6\u4f18\u5316&#xff0c;\u5b98\u65b9\u6ce8\u91ca\u76f4\u8a00\u65b0\u65b9\u6848\u7684\u541e\u5410\u4e0e\u5185\u5b58\u5360\u7528\u90fd\u4f18\u4e8e\u5206\u6bb5\u9501\u3002<\/p>\n<p>Q2&#xff1a;CHM \u4e3a\u4ec0\u4e48\u4e0d\u5141\u8bb8 null key \/ null value&#xff1f;HashMap \u5374\u5141\u8bb8&#xff1f;<\/p>\n<p>get \u8fd4\u56de null \u6709\u4e24\u79cd\u53ef\u80fd&#xff1a;key \u4e0d\u5b58\u5728\u3001\u6216\u6620\u5c04\u5230 null\u3002\u5355\u7ebf\u7a0b HashMap \u53ef\u4ee5\u518d\u8c03\u4e00\u6b21 containsKey \u6d88\u9664\u6b67\u4e49&#xff1b;\u800c CHM \u8981\u5728\u5e76\u53d1\u4e0b\u7ef4\u6301\u8fd9\u4e2a\u6b67\u4e49\u5224\u65ad&#xff0c;\u4f1a\u8ba9\u65e0\u9501\u8bfb\u7684\u8bed\u4e49\u53d8\u5f97\u590d\u6742\u4e14\u6613\u8bef\u5bfc\u8c03\u7528\u65b9&#xff08;\u4e5f\u5f71\u54cd get\/putIfAbsent\/compute \u7b49\u590d\u5408\u64cd\u4f5c\u7684\u539f\u5b50\u8bed\u4e49&#xff09;&#xff0c;\u56e0\u6b64\u8bbe\u8ba1\u4e0a\u76f4\u63a5\u62d2\u7edd null&#xff08;put \u5373\u629b NPE&#xff09;\u3002\u8fd9\u662f Doug Lea \u5728\u6e90\u7801\u6ce8\u91ca\u91cc\u70b9\u660e\u7684\u523b\u610f\u53d6\u820d\u3002<\/p>\n<p>Q3&#xff1a;\u6876\u6570\u7ec4\u957f\u5ea6\u4e3a\u4ec0\u4e48\u5fc5\u987b\u4fdd\u6301 2 \u7684\u5e42&#xff1f;<\/p>\n<p>\u4e24\u5904\u4f9d\u8d56&#xff1a;\u2460 \u4e0b\u6807\u8ba1\u7b97\u7528\u4f4d\u8fd0\u7b97 (n-1) &amp; hash \u66ff\u4ee3\u53d6\u6a21&#xff1b;\u2461 \u6269\u5bb9\u65f6 hash &amp; n \u4e00\u4f4d\u5373\u53ef\u5224\u5b9a\u8282\u70b9\u53bb\u65b0\u8868\u7684 i \u8fd8\u662f i&#043;n&#xff08;5.3&#xff09;&#xff0c;\u6574\u6761\u94fe\u9ad8\u4f4e\u62c6\u5206\u3001\u65e0\u9700\u91cd\u54c8\u5e0c\u3002<\/p>\n<p>Q4&#xff1a;sizeCtl \u8d1f\u6570\u4e24\u79cd\u542b\u4e49\u5982\u4f55\u533a\u5206&#xff1f;<\/p>\n<p>-1 \u4e13\u6307\u300c\u521d\u59cb\u5316\u4e2d\u300d&#xff08;initTable \u7684 CAS \u76ee\u6807&#xff09;&#xff1b;\u5c0f\u4e8e -1 \u8868\u793a\u300c\u6269\u5bb9\u4e2d\u300d&#xff0c;\u4e14 -(1 &#043; \u7ebf\u7a0b\u6570) \u7f16\u7801\u4e86\u53c2\u4e0e\u8005\u6570\u91cf\u2014\u2014\u9996\u4e2a\u6269\u5bb9\u7ebf\u7a0b\u628a sizeCtl CAS \u6210 (resizeStamp &lt;&lt; 16) &#043; 2&#xff08;\u5373 -(1&#043;1)&#xff09;&#xff0c;\u540e\u7eed\u6bcf\u52a0\u5165\u4e00\u4e2a\u7ebf\u7a0b &#043;1\u3002\u89c2\u5bdf jstack \u6216\u8c03 sizeCtl&#xff08;\u53cd\u5c04&#xff09;\u53ef\u786e\u8ba4\u662f\u5426\u5728\u6269\u5bb9\u3002<\/p>\n<p>Q5&#xff1a;\u6269\u5bb9\u671f\u95f4\u6b63\u5728\u8bfb\u7684\u7ebf\u7a0b\u5b89\u5168\u5417&#xff1f;\u4f1a\u4e0d\u4f1a\u8bfb\u5230\u4e22\u5931\u6216\u534a\u622a\u6570\u636e&#xff1f;<\/p>\n<p>\u5b89\u5168\u3002\u8fc1\u79fb\u662f\u300c\u590d\u5236\u5f0f\u300d\u7684&#xff1a;\u6876\u5185\u94fe\u8868\u5728\u6876\u9501\u4fdd\u62a4\u4e0b\u88ab\u590d\u5236\u91cd\u5efa\u8fdb\u65b0\u8868&#xff0c;\u65e7\u94fe\u8868\u9664\u6876\u5934\u88ab CAS \u6362\u6210 ForwardingNode \u5916\u4e0d\u518d\u88ab\u4fee\u6539&#xff1b;\u8bfb\u7ebf\u7a0b\u8981\u4e48\u8bfb\u65e7\u6876\u6b8b\u7559\u94fe&#xff08;\u5b8c\u6574&#xff09;&#xff0c;\u8981\u4e48\u7ecf ForwardingNode \u8f6c\u53d1\u5230\u65b0\u8868&#xff08;\u5b8c\u6574&#xff09;\u3002\u4e24\u4e2a\u7ed3\u6784\u5404\u81ea\u4e00\u81f4&#xff0c;\u8bfb\u7ebf\u7a0b\u53ea\u662f\u53ef\u80fd\u770b\u5230\u300c\u642c\u8d70\u524d\/\u540e\u300d\u7684\u5176\u4e2d\u4e00\u4e2a&#xff0c;\u7edd\u4e0d\u4f1a\u770b\u5230\u6495\u88c2\u7684\u6570\u636e\u2014\u2014\u4ee3\u4ef7\u662f\u5f31\u4e00\u81f4\u6027\u3002<\/p>\n<p>Q6&#xff1a;\u6811\u5316\u9608\u503c\u4e3a\u4ec0\u4e48\u662f 8&#xff1f;\u9000\u5316\u4e3a\u4ec0\u4e48\u662f 6&#xff1f;<\/p>\n<p>\u6cca\u677e\u5206\u5e03\u4e0b\u7406\u60f3\u54c8\u5e0c\u7684\u6876\u5185\u8282\u70b9\u6570 \u22658 \u7684\u6982\u7387\u7ea6\u5343\u4e07\u5206\u4e4b\u516d&#xff0c;\u8fbe\u5230 8 \u8bf4\u660e\u54c8\u5e0c\u5df2\u4e25\u91cd\u9000\u5316&#xff08;\u6216\u906d\u6076\u610f\u51b2\u7a81\u653b\u51fb&#xff09;&#xff0c;\u6b64\u65f6\u6811\u5316\u4f5c\u4e3a\u515c\u5e95&#xff1b;\u9000\u5316\u53d6 6 \u662f\u4e3a\u4e86\u5728 7 \u9644\u8fd1\u7559\u6ede\u56de\u5e26&#xff0c;\u907f\u514d\u9891\u7e41\u300c\u6811\u5316\u2194\u9000\u5316\u300d\u6296\u52a8\u3002MIN_TREEIFY_CAPACITY&#061;64 \u4fdd\u8bc1\u6876\u8db3\u591f\u591a\u65f6\u6811\u5316\u624d\u6709\u610f\u4e49\u3002<\/p>\n<p>Q7&#xff1a;size() \u8fd4\u56de\u7684\u503c\u7cbe\u786e\u5417&#xff1f;<\/p>\n<p>\u4e0d\u4fdd\u8bc1\u3002sumCount() \u4e0d\u52a0\u9501\u5730\u7d2f\u52a0 baseCount &#043; \u5404 CounterCell&#xff0c;\u7edf\u8ba1\u77ac\u95f4\u5e76\u53d1\u5199\u4ecd\u5728\u8fdb\u884c&#xff0c;\u8fd4\u56de\u503c\u662f\u8fd1\u4f3c\u503c&#xff1b;\u6587\u6863\u5b9a\u4f4d\u4e3a\u76d1\u63a7\u7edf\u8ba1\u7528\u9014\u3002\u9700\u8981\u7cbe\u786e\u5bb9\u91cf&#xff08;\u5982\u505a\u6dd8\u6c70\u3001\u914d\u989d\u5224\u65ad&#xff09;\u5e94\u5728\u4e1a\u52a1\u5c42\u81ea\u884c\u540c\u6b65\u6216\u63a5\u53d7\u8fd1\u4f3c\u3002<\/p>\n<p>Q8&#xff1a;JDK 8 \u7684 computeIfAbsent \u6709\u4ec0\u4e48\u8457\u540d\u5927\u5751&#xff1f;<\/p>\n<p>\u56de\u8c03\u5185\u9012\u5f52\u66f4\u65b0\u540c\u4e00\u4e2a key \u4f1a\u6b7b\u5faa\u73af&#xff08;\u94fe\u8868\u8d8a\u63d2\u8d8a\u957f \/ \u6216\u884c\u4e3a\u5f02\u5e38&#xff09;&#xff0c;\u8be5\u95ee\u9898\u5728 JDK 9&#043; \u901a\u8fc7 ReservationNode \u5360\u4f4d\u68c0\u6d4b\u4fee\u590d\u2014\u2014\u9012\u5f52\u66f4\u65b0\u4f1a\u629b IllegalStateException(&#034;Recursive update&#034;)\u3002JDK 8 \u4e0a\u7ebf\u7684\u7cfb\u7edf\u8981\u8b66\u60d5&#xff1a;mappingFunction \u91cc\u82e5\u89e6\u53d1\u4e86\u5bf9\u540c\u4e00 CHM \u540c key \u7684\u8bfb\u5199&#xff08;\u5982\u56de\u8c03\u91cc\u67e5\u7f13\u5b58\u3001Spring \u65e9\u671f\u5d4c\u5957 bean \u52a0\u8f7d&#xff09;&#xff0c;\u53ef\u80fd\u76f4\u63a5\u6253\u6ee1 CPU\u3002\u89c4\u907f&#xff1a;\u56de\u8c03\u5185\u7edd\u4e0d\u8bbf\u95ee\u540c\u4e00\u4e2a key\u3002<\/p>\n<p>Q9&#xff1a;CHM \u7684\u8fed\u4ee3\u5668\u4e0e HashMap \u7684\u6709\u4ec0\u4e48\u672c\u8d28\u533a\u522b&#xff1f;<\/p>\n<p>HashMap \u8fed\u4ee3\u5668\u662f fail-fast&#xff1a;\u904d\u5386\u671f\u95f4\u7ed3\u6784\u6027\u4fee\u6539\u7acb\u523b\u629b ConcurrentModificationException&#xff08;\u9760 modCount \u68c0\u6d4b&#xff09;&#xff1b;CHM \u8fed\u4ee3\u5668\u662f\u5f31\u4e00\u81f4&#xff1a;\u65e0\u9501\u3001\u4e0d\u629b\u5f02\u5e38\u3001\u5c3d\u529b\u770b\u5230\u904d\u5386\u5f00\u59cb\u65f6\u7684\u5feb\u7167\u5e76\u5bb9\u5fcd\u5e76\u53d1\u4fee\u6539&#xff08;7.3&#xff09;\u3002\u6279\u91cf\u62f7\u8d1d\/\u8f6c\u79fb\/\u805a\u5408\u8bf7\u7528 CHM \u8fed\u4ee3\u5668\u6216 forEach&#xff0c;\u522b\u62c5\u5fc3\u904d\u5386\u4e2d\u88ab\u6539\u3002<\/p>\n<p>Q10&#xff1a;JDK 9~17 \u91cc CHM \u7ed3\u6784\u6709\u53d8\u5316\u5417&#xff1f;<\/p>\n<p>\u6838\u5fc3\u7ed3\u6784&#xff08;\u6876\u6570\u7ec4 &#043; Node &#043; TreeBin &#043; \u6269\u5bb9\u534f\u4f5c &#043; CounterCell&#xff09;\u81ea JDK 8 \u5b9a\u578b\u540e\u4fdd\u6301\u7a33\u5b9a&#xff1b;\u540e\u7eed\u4e3b\u8981\u662f\u884c\u4e3a\u4fee\u590d\u4e0e\u589e\u5f3a&#xff1a;computeIfAbsent \u9012\u5f52\u68c0\u6d4b&#xff08;JDK 9&#xff09;\u3001remove \u76f8\u5173\u8fb9\u7f18\u5e76\u53d1\u4fee\u590d\u3001\u6587\u6863\u4e0e Javadoc \u5b8c\u5584\u7b49\u3002\u5206\u6790 JDK 8 \u6e90\u7801\u7684\u7ed3\u8bba\u5728\u5f53\u4ee3\u7248\u672c\u4f9d\u7136\u6210\u7acb\u2014\u2014\u8fd9\u4e5f\u662f\u5b83\u503c\u5f97\u7cbe\u8bfb\u7684\u539f\u56e0\u3002<\/p>\n<hr \/>\n<h3>13. \u53c2\u8003\u8d44\u6599\u4e0e\u5ef6\u4f38<\/h3>\n<ul>\n<li>OpenJDK JDK 8 ConcurrentHashMap.java&#xff08;\u672c\u6587\u6e90\u7801\u4f9d\u636e&#xff0c;\u6e90\u7801\u91cc Doug Lea \u7684\u957f\u6ce8\u91ca\u503c\u5f97\u9010\u884c\u8bfb&#xff09;<\/li>\n<li>OpenJDK JDK 8 LongAdder.java&#xff08;CounterCell \u8ba1\u6570\u7684\u601d\u60f3\u6e90\u5934&#xff09;<\/li>\n<li>OpenJDK JDK 7 ConcurrentHashMap.java&#xff08;\u5206\u6bb5\u9501\u5b9e\u73b0\u5bf9\u7167&#xff09;<\/li>\n<li>ConcurrentHashMap (Java SE 8 \u5b98\u65b9\u6587\u6863)<\/li>\n<li>\u300aJava \u5e76\u53d1\u7f16\u7a0b\u7684\u827a\u672f\u300b\u65b9\u817e\u98de \u7b49&#xff1a;\u7b2c 6 \u7ae0 ConcurrentHashMap \u8be6\u89e3<\/li>\n<li>\u300a\u6df1\u5165\u7406\u89e3 Java \u865a\u62df\u673a\u300b\u5468\u5fd7\u660e&#xff1a;\u9501\u4f18\u5316\u4e0e\u5e76\u53d1\u7535\u9762\u80cc\u666f\u77e5\u8bc6<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u57fa\u4e8e&#xff1a;OpenJDK JDK 8u \u7684 java.util.concurrent.ConcurrentHashMap&#xff08;\u5bf9\u7167 JDK 7 \u5206\u6bb5\u9501\u5b9e\u73b0\u4e0e JDK 9 \u6f14\u8fdb&#xff09; \u672c\u6587\u4ee5\u6e90\u7801\u89e3\u6790\u4e3a\u4e3b\u7ebf&#xff0c;\u9010\u6bb5\u62c6\u89e3 JDK 8 \u7248 ConcurrentHashMap \u7684\u6838\u5fc3\u5b9e\u73b0&#xff1a;\u5b57\u6bb5\u4e0e sizeCtl \u8bed\u4e49\u3001putVal \u5168\u94fe\u8def\u3001\u591a\u7ebf\u7a0b\u534f\u4f5c\u6269\u5bb9\u3001\u65e0\u9501\u8bfb\u3001\u57fa\u4e8e CounterCell \u7684\u8ba1\u6570\u3001\u7ea2\u9ed1\u6811\u5316\u4e0e TreeBin&amp;#<\/p>\n","protected":false},"author":2,"featured_media":103209,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[6928,99,586],"topic":[],"class_list":["post-103210","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-6928","tag-java","tag-586"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>\u3010\u591a\u7ebf\u7a0b\u3011-ConcurrentHashMap \u6e90\u7801\u89e3\u6790 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.wsisp.com\/helps\/103210.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"\u3010\u591a\u7ebf\u7a0b\u3011-ConcurrentHashMap \u6e90\u7801\u89e3\u6790 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"\u57fa\u4e8e&#xff1a;OpenJDK JDK 8u \u7684 java.util.concurrent.ConcurrentHashMap&#xff08;\u5bf9\u7167 JDK 7 \u5206\u6bb5\u9501\u5b9e\u73b0\u4e0e JDK 9 \u6f14\u8fdb&#xff09; \u672c\u6587\u4ee5\u6e90\u7801\u89e3\u6790\u4e3a\u4e3b\u7ebf&#xff0c;\u9010\u6bb5\u62c6\u89e3 JDK 8 \u7248 ConcurrentHashMap \u7684\u6838\u5fc3\u5b9e\u73b0&#xff1a;\u5b57\u6bb5\u4e0e sizeCtl \u8bed\u4e49\u3001putVal \u5168\u94fe\u8def\u3001\u591a\u7ebf\u7a0b\u534f\u4f5c\u6269\u5bb9\u3001\u65e0\u9501\u8bfb\u3001\u57fa\u4e8e CounterCell \u7684\u8ba1\u6570\u3001\u7ea2\u9ed1\u6811\u5316\u4e0e TreeBin&amp;#\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/103210.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-09-09T18:57:04+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/09\/20260909185701-6aa1abfdd82fc.png\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"26 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/103210.html\",\"url\":\"https:\/\/www.wsisp.com\/helps\/103210.html\",\"name\":\"\u3010\u591a\u7ebf\u7a0b\u3011-ConcurrentHashMap \u6e90\u7801\u89e3\u6790 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\",\"isPartOf\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/#website\"},\"datePublished\":\"2026-09-09T18:57:04+00:00\",\"dateModified\":\"2026-09-09T18:57:04+00:00\",\"author\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41\"},\"breadcrumb\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/103210.html#breadcrumb\"},\"inLanguage\":\"zh-Hans\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.wsisp.com\/helps\/103210.html\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/103210.html#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"\u9996\u9875\",\"item\":\"https:\/\/www.wsisp.com\/helps\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"\u3010\u591a\u7ebf\u7a0b\u3011---ConcurrentHashMap \u6e90\u7801\u89e3\u6790\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#website\",\"url\":\"https:\/\/www.wsisp.com\/helps\/\",\"name\":\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\",\"description\":\"\u9999\u6e2f\u670d\u52a1\u5668_\u9999\u6e2f\u4e91\u670d\u52a1\u5668\u8d44\u8baf_\u670d\u52a1\u5668\u5e2e\u52a9\u6587\u6863_\u670d\u52a1\u5668\u6559\u7a0b\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.wsisp.com\/helps\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"zh-Hans\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41\",\"name\":\"admin\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"zh-Hans\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery\",\"contentUrl\":\"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery\",\"caption\":\"admin\"},\"sameAs\":[\"http:\/\/wp.wsisp.com\"],\"url\":\"https:\/\/www.wsisp.com\/helps\/author\/admin\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"\u3010\u591a\u7ebf\u7a0b\u3011-ConcurrentHashMap \u6e90\u7801\u89e3\u6790 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.wsisp.com\/helps\/103210.html","og_locale":"zh_CN","og_type":"article","og_title":"\u3010\u591a\u7ebf\u7a0b\u3011-ConcurrentHashMap \u6e90\u7801\u89e3\u6790 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","og_description":"\u57fa\u4e8e&#xff1a;OpenJDK JDK 8u \u7684 java.util.concurrent.ConcurrentHashMap&#xff08;\u5bf9\u7167 JDK 7 \u5206\u6bb5\u9501\u5b9e\u73b0\u4e0e JDK 9 \u6f14\u8fdb&#xff09; \u672c\u6587\u4ee5\u6e90\u7801\u89e3\u6790\u4e3a\u4e3b\u7ebf&#xff0c;\u9010\u6bb5\u62c6\u89e3 JDK 8 \u7248 ConcurrentHashMap \u7684\u6838\u5fc3\u5b9e\u73b0&#xff1a;\u5b57\u6bb5\u4e0e sizeCtl \u8bed\u4e49\u3001putVal \u5168\u94fe\u8def\u3001\u591a\u7ebf\u7a0b\u534f\u4f5c\u6269\u5bb9\u3001\u65e0\u9501\u8bfb\u3001\u57fa\u4e8e CounterCell \u7684\u8ba1\u6570\u3001\u7ea2\u9ed1\u6811\u5316\u4e0e TreeBin&amp;#","og_url":"https:\/\/www.wsisp.com\/helps\/103210.html","og_site_name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","article_published_time":"2026-09-09T18:57:04+00:00","og_image":[{"url":"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/09\/20260909185701-6aa1abfdd82fc.png"}],"author":"admin","twitter_card":"summary_large_image","twitter_misc":{"\u4f5c\u8005":"admin","\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4":"26 \u5206"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.wsisp.com\/helps\/103210.html","url":"https:\/\/www.wsisp.com\/helps\/103210.html","name":"\u3010\u591a\u7ebf\u7a0b\u3011-ConcurrentHashMap \u6e90\u7801\u89e3\u6790 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","isPartOf":{"@id":"https:\/\/www.wsisp.com\/helps\/#website"},"datePublished":"2026-09-09T18:57:04+00:00","dateModified":"2026-09-09T18:57:04+00:00","author":{"@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41"},"breadcrumb":{"@id":"https:\/\/www.wsisp.com\/helps\/103210.html#breadcrumb"},"inLanguage":"zh-Hans","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.wsisp.com\/helps\/103210.html"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.wsisp.com\/helps\/103210.html#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"\u9996\u9875","item":"https:\/\/www.wsisp.com\/helps"},{"@type":"ListItem","position":2,"name":"\u3010\u591a\u7ebf\u7a0b\u3011---ConcurrentHashMap \u6e90\u7801\u89e3\u6790"}]},{"@type":"WebSite","@id":"https:\/\/www.wsisp.com\/helps\/#website","url":"https:\/\/www.wsisp.com\/helps\/","name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","description":"\u9999\u6e2f\u670d\u52a1\u5668_\u9999\u6e2f\u4e91\u670d\u52a1\u5668\u8d44\u8baf_\u670d\u52a1\u5668\u5e2e\u52a9\u6587\u6863_\u670d\u52a1\u5668\u6559\u7a0b","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.wsisp.com\/helps\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"zh-Hans"},{"@type":"Person","@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41","name":"admin","image":{"@type":"ImageObject","inLanguage":"zh-Hans","@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/image\/","url":"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery","contentUrl":"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery","caption":"admin"},"sameAs":["http:\/\/wp.wsisp.com"],"url":"https:\/\/www.wsisp.com\/helps\/author\/admin"}]}},"_links":{"self":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/103210","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/comments?post=103210"}],"version-history":[{"count":0,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/103210\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media\/103209"}],"wp:attachment":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media?parent=103210"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/categories?post=103210"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/tags?post=103210"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/topic?post=103210"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}