{"id":70589,"date":"2026-02-02T04:41:02","date_gmt":"2026-02-01T20:41:02","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/70589.html"},"modified":"2026-02-02T04:41:02","modified_gmt":"2026-02-01T20:41:02","slug":"java%e6%80%a7%e8%83%bd%e4%bc%98%e5%8c%96%e6%8a%80%e5%b7%a7","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/70589.html","title":{"rendered":"Java\u6027\u80fd\u4f18\u5316\u6280\u5de7"},"content":{"rendered":"

1. \u5b57\u7b26\u4e32\u64cd\u4f5c\u4f18\u5316<\/h2>\n

1.1 \u4f7f\u7528StringBuilder\u8fdb\u884c\u5b57\u7b26\u4e32\u62fc\u63a5<\/h3>\n

\/\/ \u274c \u95ee\u9898\u4ee3\u7801：\u5728\u5faa\u73af\u4e2d\u4f7f\u7528"+"\u62fc\u63a5\u5b57\u7b26\u4e32<\/span>
\nString<\/span> result =<\/span> ""<\/span>;<\/span>
\nfor<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> 10000<\/span>;<\/span> i++<\/span>)<\/span> {<\/span>
\n result +=<\/span> i;<\/span> \/\/ \u6bcf\u6b21\u5faa\u73af\u90fd\u521b\u5efa\u65b0\u7684StringBuilder\u5bf9\u8c61<\/span>
\n}<\/span><\/p>\n

\/\/ \u2705 \u4f18\u5316\u65b9\u6848：\u663e\u5f0f\u4f7f\u7528StringBuilder<\/span>
\nStringBuilder<\/span> sb =<\/span> new<\/span> StringBuilder<\/span>(<\/span>)<\/span>;<\/span>
\nfor<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> 10000<\/span>;<\/span> i++<\/span>)<\/span> {<\/span>
\n sb.<\/span>append<\/span>(<\/span>i)<\/span>;<\/span>
\n}<\/span>
\nString<\/span> result =<\/span> sb.<\/span>toString<\/span>(<\/span>)<\/span>;<\/span><\/p>\n

\u6848\u4f8b\u4ee3\u7801<\/h4>\n

public<\/span> class<\/span> StringConcatOptimize<\/span> {<\/span>
\n \/\/ \u6d4b\u8bd5\u5faa\u73af\u6b21\u6570：10\u4e07\u6b21（\u8db3\u591f\u653e\u5927\u6027\u80fd\u5dee\u5f02）<\/span>
\n private<\/span> static<\/span> final<\/span> int<\/span> LOOP_COUNT =<\/span> 100000<\/span>;<\/span><\/p>\n

public<\/span> static<\/span> void<\/span> main<\/span>(<\/span>String<\/span>[<\/span>]<\/span> args)<\/span> {<\/span>
\n \/\/ 1. \u65b9\u5f0f1：\u5faa\u73af\u4e2d\u4f7f\u7528"+"\u62fc\u63a5\u5b57\u7b26\u4e32（\u4f4e\u6548）<\/span>
\n long<\/span> plusConcatTime =<\/span> testPlusConcat<\/span>(<\/span>)<\/span>;<\/span>
\n \/\/ 2. \u65b9\u5f0f2：\u663e\u5f0f\u4f7f\u7528StringBuilder\u62fc\u63a5（\u9ad8\u6548）<\/span>
\n long<\/span> stringBuilderTime =<\/span> testStringBuilderConcat<\/span>(<\/span>)<\/span>;<\/span><\/p>\n

\/\/ \u6253\u5370\u7ed3\u679c<\/span>
\n System<\/span>.<\/span>out.<\/span>println<\/span>(<\/span>"===== \u5b57\u7b26\u4e32\u62fc\u63a5\u6027\u80fd\u5bf9\u6bd4 ====="<\/span>)<\/span>;<\/span>
\n System<\/span>.<\/span>out.<\/span>println<\/span>(<\/span>"\u5faa\u73af\u4e2d\u4f7f\u7528\\\\"+\\\\"\u62fc\u63a5\u8017\u65f6："<\/span> +<\/span> plusConcatTime +<\/span> " \u6beb\u79d2"<\/span>)<\/span>;<\/span>
\n System<\/span>.<\/span>out.<\/span>println<\/span>(<\/span>"\u4f7f\u7528StringBuilder\u62fc\u63a5\u8017\u65f6："<\/span> +<\/span> stringBuilderTime +<\/span> " \u6beb\u79d2"<\/span>)<\/span>;<\/span>
\n }<\/span><\/p>\n

\/**
\n * \u6d4b\u8bd5\u5faa\u73af\u4e2d\u7528"+"\u62fc\u63a5\u5b57\u7b26\u4e32\u7684\u8017\u65f6
\n *\/<\/span>
\n private<\/span> static<\/span> long<\/span> testPlusConcat<\/span>(<\/span>)<\/span> {<\/span>
\n String<\/span> result =<\/span> ""<\/span>;<\/span>
\n long<\/span> startTime =<\/span> System<\/span>.<\/span>currentTimeMillis<\/span>(<\/span>)<\/span>;<\/span>
\n for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> LOOP_COUNT;<\/span> i++<\/span>)<\/span> {<\/span>
\n \/\/ \u6bcf\u6b21\u5faa\u73af\u90fd\u4f1a\u521b\u5efa\u65b0\u7684StringBuilder，\u62fc\u63a5\u540e\u8f6cString<\/span>
\n result +=<\/span> i;<\/span>
\n }<\/span>
\n long<\/span> endTime =<\/span> System<\/span>.<\/span>currentTimeMillis<\/span>(<\/span>)<\/span>;<\/span>
\n \/\/ \u6253\u5370\u7ed3\u679c\u957f\u5ea6（\u9a8c\u8bc1\u62fc\u63a5\u5b8c\u6210）<\/span>
\n System<\/span>.<\/span>out.<\/span>println<\/span>(<\/span>"\\\\"+\\\\"\u62fc\u63a5\u7ed3\u679c\u957f\u5ea6："<\/span> +<\/span> result.<\/span>length<\/span>(<\/span>)<\/span>)<\/span>;<\/span>
\n return<\/span> endTime –<\/span> startTime;<\/span>
\n }<\/span><\/p>\n

\/**
\n * \u6d4b\u8bd5\u663e\u5f0f\u4f7f\u7528StringBuilder\u62fc\u63a5\u5b57\u7b26\u4e32\u7684\u8017\u65f6
\n *\/<\/span>
\n private<\/span> static<\/span> long<\/span> testStringBuilderConcat<\/span>(<\/span>)<\/span> {<\/span>
\n \/\/ \u521d\u59cb\u5316StringBuilder（\u53ef\u6307\u5b9a\u521d\u59cb\u5bb9\u91cf\u8fdb\u4e00\u6b65\u4f18\u5316）<\/span>
\n StringBuilder<\/span> sb =<\/span> new<\/span> StringBuilder<\/span>(<\/span>LOOP_COUNT *<\/span> 5<\/span>)<\/span>;<\/span> \/\/ \u9884\u4f30\u6bcf\u4e2a\u6570\u5b57\u53605\u4e2a\u5b57\u7b26，\u51cf\u5c11\u6269\u5bb9<\/span>
\n long<\/span> startTime =<\/span> System<\/span>.<\/span>currentTimeMillis<\/span>(<\/span>)<\/span>;<\/span>
\n for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i <<\/span> LOOP_COUNT;<\/span> i++<\/span>)<\/span> {<\/span>
\n \/\/ \u76f4\u63a5\u5728\u539f\u6709\u7f13\u51b2\u533a\u8ffd\u52a0，\u65e0\u65b0\u5bf9\u8c61\u521b\u5efa<\/span>
\n sb.<\/span>append<\/span>(<\/span>i)<\/span>;<\/span>
\n }<\/span>
\n String<\/span> result =<\/span> sb.<\/span>toString<\/span>(<\/span>)<\/span>;<\/span>
\n long<\/span> endTime =<\/span> System<\/span>.<\/span>currentTimeMillis<\/span>(<\/span>)<\/span>;<\/span>
\n \/\/ \u6253\u5370\u7ed3\u679c\u957f\u5ea6（\u9a8c\u8bc1\u62fc\u63a5\u5b8c\u6210）<\/span>
\n System<\/span>.<\/span>out.<\/span>println<\/span>(<\/span>"StringBuilder\u62fc\u63a5\u7ed3\u679c\u957f\u5ea6："<\/span> +<\/span> result.<\/span>length<\/span>(<\/span>)<\/span>)<\/span>;<\/span>
\n return<\/span> endTime –<\/span> startTime;<\/span>
\n }<\/span>
\n}<\/span><\/p>\n