\u76ee\u5f55<\/p>\n
\n
\u4e00\u3001\u52a8\u6001sql(\u63a5SSM\u6846\u67b6-MyBatis2\u4e2d\u7684\u52a8\u6001sql)<\/p>\n
\u4e8c\u3001MyBatis\u7684\u7f13\u5b58\u673a\u5236<\/p>\n
\u4e09\u3001\u6570\u636e\u5e93\u4e2d\u5217\u540d\u548cpojo\u4e2d\u7684\u5b9e\u4f53\u7c7b\u4e0d\u4e00\u81f4\u95ee\u9898<\/p>\n
\u56db\u3001\u591a\u8868\u5173\u8054\u67e5\u8be2<\/p>\n
1.<choose><when><otherwise>\u6807\u7b7e：<\/p>\n
（1）\u5355\u6761\u4ef6\u67e5\u8be2(\u53ea\u53d6\u5176\u4e00)，\u8fd9\u662f\u4e00\u5957\u6807\u7b7e，\u529f\u80fd\u7c7b\u4f3c\u4e8eif…else if…else if…else\u3002<\/p>\n
（2）\u8fd9\u4e2a\u6807\u7b7e\u9700\u8981\u5199\u5728<where><\/where>\u6807\u7b7e\u91cc\u9762\u3002<\/p>\n
（3）\u683c\u5f0f：<choose><when test="\u6761\u4ef6">sql\u8bed\u53e5<\/when> <when test="\u6761\u4ef6">sql\u8bed\u53e5<\/when> <when test="\u6761\u4ef6">sql\u8bed\u53e5<\/when> <otherwise>sql\u8bed\u53e5<\/otherwise><\/choose>\u3002<\/p>\n
（4）when\u4e2d\u53d6\u5176\u4e2d\u7684\u4e00\u4e2a，\u4e0d\u4f1a\u8ffd\u52a0\u591a\u4e2a\u6761\u4ef6，\u5982\u679c\u6709\u591a\u4e2a\u6761\u4ef6，\u53ea\u53d6\u6700\u524d\u9762\u7684\u90a3\u4e2a，\u5982\u679c\u90fd\u4e0d\u6ee1\u8db3\u5c31\u4e0d\u67e5\u6570\u636e\u4e86\u3002<\/p>\n
2.<set>\u6807\u7b7e：<\/p>\n
（1）\u7528\u4e8e\u7ef4\u62a4update\u8bed\u53e5\u4e2d\u7684set\u5b50\u53e5，\u529f\u80fd\u5982\u4e0b：<\/p>\n
（2）\u683c\u5f0f：<set> <if test="username != null and username != ''"> \u8981\u4fee\u6539\u7684\u52171, <\/if> <if test="password != null and password != ''"> \u8981\u4fee\u6539\u7684\u52172, <\/if> <if test="city != null and city != ''"> \u8981\u4fee\u6539\u7684\u52173 <\/if><\/set>\u3002<\/p>\n
（3）set\u6807\u7b7e\u91cc\u9762\u53ef\u4ee5\u4f7f\u7528if\u6807\u7b7e\u5b8c\u6210\u8bed\u53e5\u7684\u6dfb\u52a0，\u53ef\u4ee5\u6839\u636e\u4e0d\u540c\u7684\u6761\u4ef6\u6dfb\u52a0\u4e0d\u540c\u7684\u8bed\u53e5\u3002<\/p>\n
（4）\u5982\u679c\u8981\u4fee\u6539\u591a\u4e2a\u6570\u636e，\u8981\u4f7f\u7528\u9017\u53f7\u9694\u5f00\u3002<\/p>\n
3.<bind>\u6807\u7b7e：<\/p>\n
（1）\u7528\u4e8e\u5bf9\u6570\u636e\u8fdb\u884c\u518d\u52a0\u5de5，\u7528\u4e8e\u6a21\u7cca\u67e5\u8be2，\u8fd9\u4e2a\u52a0\u5de5\u662f\u5728\u6570\u636e\u4f7f\u7528\u4e4b\u524d\u505a\u52a0\u5de5\u7684，\u52a0\u5de5\u5b8c\u4e4b\u540e\u518d\u53bb\u4f7f\u7528\u3002<\/p>\n
（2）\u683c\u5f0f：<bind name="\u8981\u52a8\u6001\u63a5\u6536\u7684\u6570\u636e\u540d" value="\u5bf9\u6570\u636e\u8fdb\u884c\u52a0\u5de5\u8fdb\u884c\u52a0\u5de5" \/>\u3002<\/p>\n
（3）bind\u6807\u7b7e\u8981\u5199\u5728select\u6807\u7b7e\u91cc\u9762\u3002<\/p>\n
4.concat\u51fd\u6570：<\/p>\n
（1）\u8fd9\u4e2a\u51fd\u6570\u5728mysql\u4e2d\u662f\u7528\u4e8e\u62fc\u63a5\u5b57\u7b26\u4e32\u4e32\u7684，\u8981\u62fc\u63a5\u591a\u4e2a\u5b57\u7b26\u4e32\u9700\u8981\u4f7f\u7528\u9017\u53f7\u5206\u9694\u3002<\/p>\n
（2）\u683c\u5f0f：concat("\u5b57\u7b26\u4e321","\u5b57\u7b26\u4e322","\u5b57\u7b26\u4e323")\u3002<\/p>\n
（3）\u8fd9\u4e2a\u51fd\u6570\u6709\u70b9\u50cfjava\u4e2dStringBuffer\u91cc\u9762\u7684append\u65b9\u6cd5\u3002<\/p>\n
5.<foreach>\u6807\u7b7e：<\/p>\n
（1）\u5728\u4e00\u4e2a\u8303\u56f4\u4e2d\u67e5\u8be2\u3002<\/p>\n
（2）\u7528\u4e8e\u5728SQL\u8bed\u53e5\u4e2d\u904d\u5386\u96c6\u5408\u53c2\u6570，\u5728in\u67e5\u8be2\u4e2d\u4f7f\u7528\u3002<\/p>\n
（3）\u5c5e\u6027：<\/p>\n
6.<sql>\\\\<include>\u6807\u7b7e：<\/p>\n
（1）\u52a8\u6001\u9009\u62e9\u8981\u67e5\u8be2\u7684\u5217\u3002<\/p>\n
（2）sql\u6807\u7b7e\u7528\u4e8e\u63d0\u53d6SQL\u8bed\u53e5，include\u6807\u7b7e\u7528\u4e8e\u5f15\u7528SQL\u8bed\u53e5\u3002<\/p>\n
（3）\u683c\u5f0f：<sql id="s1"> uid,username<\/sql> <select id="selChose" resultType="Users"> select <include refid="s1"><\/include> from users<\/select>\u3002<\/p>\n
（4）\u6ce8\u610f：include\u6807\u7b7e\u662f\u901a\u8fc7id\u53bb\u7ed1\u5b9asql\u6807\u7b7e\u7684，sql\u6807\u7b7e\u53ef\u4ee5\u6709\u591a\u4e2a\u3002<\/p>\n
7.\u6848\u4f8b （1）\u6620\u5c04\u6587\u4ef6\u4e2d\u7684\u5185\u5bb9：<\/p>\n
<?xml version="1.0" encoding="UTF-8" ?>
\n<!DOCTYPE mapper
\n PUBLIC "-\/\/mybatis.org\/\/DTD Mapper 3.0\/\/EN"
\n "http:\/\/mybatis.org\/dtd\/mybatis-3-mapper.dtd">
\n<!–\u5173\u8054\u63a5\u53e3\u4e0e\u6620\u5c04\u6587\u4ef6–>
\n<mapper namespace="com.mybatis.mapper.UserMapper">
\n <!–\u901a\u8fc7if\u6807\u7b7e\u5b9e\u73b0\u52a8\u6001sql\u8bed\u53e5–>
\n <!–where 1=1 \u662f\u56e0\u4e3a\u6211\u4eec\u60f3\u8981\u4f7f\u7528and\u62fc\u63a5\u6761\u4ef6，\u4f46\u662fwhere\u8bed\u53e5\u5fc5\u987b\u51fa\u73b0\u5728and\u524d\u9762，\u6240\u4ee5\u8981\u628awhere\u6d88\u8017\u6389–>
\n <select id="selAll" resultType="Users">
\n select * from users where 1 = 1
\n <if test="uid != 0">
\n and uid = #{uid}
\n <\/if>
\n <if test="username != null and username != ''">
\n and username = #{username}
\n <\/if>
\n <if test="password != null and password != ''">
\n and password = #{password}
\n <\/if>
\n <if test="city != null and city != ''">
\n and city = #{city}
\n <\/if>
\n <\/select><\/p>\n
<!–\u89e3\u51b3where\u95ee\u9898–>
\n <select id="selAll2" resultType="Users">
\n select * from users
\n <where>
\n <if test="uid != 0">
\n and uid = #{uid}
\n <\/if>
\n <if test="username != null and username != ''">
\n and username = #{username}
\n <\/if>
\n <if test="password != null and password != ''">
\n and password = #{password}
\n <\/if>
\n <if test="city != null and city != ''">
\n and city = #{city}
\n <\/if>
\n <\/where>
\n <\/select><\/p>\n
<select id="selBy3" resultType="Users">
\n select * from users
\n <where>
\n <choose>
\n <when test="uid != 0">
\n uid = #{uid}
\n <\/when>
\n <when test="username != null and username != ''">
\n username = #{username}
\n <\/when>
\n <otherwise>
\n city = #{city}
\n <\/otherwise>
\n <\/choose>
\n <\/where>
\n <\/select><\/p>\n
<update id="updateBy">
\n update users
\n <set>
\n <if test="username != null and username != ''">
\n username = #{username},
\n <\/if>
\n <if test="password != null and password != ''">
\n password = #{password},
\n <\/if>
\n <if test="city != null and city != ''">
\n city = #{city}
\n <\/if>
\n <\/set>
\n where uid = #{uid}
\n <\/update><\/p>\n
<!–\u65b9\u5f0f\u4e00–>
\n <!–bind\u5728\u6570\u636e\u4f7f\u7528\u4e4b\u524d\u505a\u52a0\u5de5\u5904\u7406–>
\n <select id="selLike" resultType="Users">
\n <bind name="param1" value="'%' + param1 + '%'"\/>
\n select * from users where city like #{param1}
\n <\/select>
\n <!–\u65b9\u5f0f\u4e8c \u4f7f\u7528\u51fd\u6570concat：\u6709\u70b9\u50cfStringBuffer\u91cc\u9762\u7684append\u65b9\u6cd5–>
\n <select id="selLike2" resultType="Users">
\n <bind name="param1" value="'%' + param1 + '%'"\/>
\n select * from users where city like concat ('%',#{param1},'%')
\n <\/select><\/p>\n
<!–foreach\u6807\u7b7e\u4e2d，\u62fc\u63a5\u6570\u636e\u4e3a(4,5,9)
\n for(Integer i : list){
\n i\u4ee3\u8868list\u96c6\u5408\u4e2d\u7684\u6bcf\u4e00\u4e2a\u5143\u7d20
\n }
\n –>
\n <select id="selIn" resultType="Users">
\n select * from users where uid in
\n <foreach collection="list" open="(" separator="," close=")" item="i">
\n #{i}
\n <\/foreach>
\n <\/select><\/p>\n
<!–\u6839\u636e\u7ec4\u5408\u6765\u6307\u5b9a\u67e5\u8be2\u5217–>
\n <sql id="s1">
\n uid,username
\n <\/sql>
\n <sql id="s2">
\n username,city
\n <\/sql>
\n <select id="selChose" resultType="Users">
\n select
\n <include refid="s2"><\/include>
\n from users
\n <\/select>
\n<\/mapper> <\/p>\n
（2）\u63a5\u53e3\u4e2d\u7684\u5185\u5bb9：<\/p>\n
package com.mybatis.mapper;<\/p>\n
import com.mybatis.pojo.Users;<\/p>\n
import java.util.List;<\/p>\n
public interface UserMapper {
\n List<Users> selAll(Users user);<\/p>\n
List<Users> selAll2(Users user);<\/p>\n
List<Users> selBy3(Users user);<\/p>\n
int updateBy(Users user);<\/p>\n
List<Users> selLike(String city);<\/p>\n
List<Users> selLike2(String city);<\/p>\n
List<Users> selIn(List<Integer> list);<\/p>\n
List<Users> selChose();
\n} <\/p>\n
（3）\u4f7f\u7528：<\/p>\n
package com.mybatis.test;<\/p>\n
import com.mybatis.mapper.UserMapper;
\nimport com.mybatis.pojo.Users;
\nimport org.apache.ibatis.io.Resources;
\nimport org.apache.ibatis.session.SqlSession;
\nimport org.apache.ibatis.session.SqlSessionFactory;
\nimport org.apache.ibatis.session.SqlSessionFactoryBuilder;
\nimport org.junit.Test;<\/p>\n
import javax.xml.bind.annotation.XmlAnyAttribute;
\nimport java.io.IOException;
\nimport java.io.InputStream;
\nimport java.util.ArrayList;
\nimport java.util.List;<\/p>\n
public class Demo {
\n SqlSession session;
\n UserMapper mapper;
\n public Demo(){
\n \/\/\u52a0\u8f7dapplication-dao.xml
\n String resource = "application-dao.xml";
\n try {
\n \/\/\u5c06\u6587\u4ef6\u8f6c\u6362\u4e3a\u6d41\u5bf9\u8c61
\n InputStream resourceAsStream = Resources.getResourceAsStream(resource);
\n \/\/\u83b7\u53d6SqlSessionFactory\u5bf9\u8c61
\n SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
\n \/\/\u83b7\u53d6\u53d1\u9001sql\u8bed\u53e5\u7684\u5bf9\u8c61
\n session = sqlSessionFactory.openSession();
\n \/\/\u83b7\u53d6\u63a5\u53e3\u5bf9\u8c61
\n mapper = session.getMapper(UserMapper.class);
\n } catch (IOException e) {
\n e.printStackTrace();
\n }
\n }<\/p>\n
\/**
\n * \u67e5\u8be2
\n *\/
\n @Test
\n public void selAll(){
\n Users u = new Users();
\n\/\/ u.setUid(22);
\n\/\/ u.setUsername("\u5c0f\u4e54");
\n\/\/ u.setPassword("123321");
\n u.setCity("\u6c5f\u5357");
\n List<Users> users = mapper.selAll(u);
\n for (Users user : users) {
\n System.out.println(user);
\n }
\n }<\/p>\n
@Test
\n public void selAll2(){
\n Users u = new Users();
\n\/\/ u.setUid(22);
\n u.setUsername("\u5c0f\u4e54");
\n u.setPassword("123321");
\n\/\/ u.setCity("\u6c5f\u5357");
\n List<Users> users = mapper.selAll2(u);
\n for (Users user : users) {
\n System.out.println(user);
\n }
\n }<\/p>\n
@Test
\n public void selBy3(){
\n Users u = new Users();
\n\/\/ u.setUid(22);
\n\/\/ u.setUsername("\u5c0f\u4e54");
\n\/\/ u.setCity("\u6c5f\u5357");
\n List<Users> users = mapper.selBy3(u);
\n for (Users user : users) {
\n System.out.println(user);
\n }
\n }<\/p>\n
@Test
\n public void update(){
\n Users u = new Users();
\n u.setUid(26);
\n\/\/ u.setPassword("123");
\n\/\/ u.setCity("\u91cd\u5e86");
\n u.setUsername("\u590f\u8749");
\n int n = mapper.updateBy(u);
\n System.out.println(n == 1 ? "\u4fee\u6539\u6210\u529f" : "\u4fee\u6539\u5931\u8d25");
\n session.commit();
\n }<\/p>\n
@Test
\n public void like(){
\n\/\/ List<Users> users = mapper.selLike("\u6c5f");
\n List<Users> users = mapper.selLike2("\u6c5f");
\n for (Users user : users) {
\n System.out.println(user);
\n }
\n }<\/p>\n
@Test
\n public void selIn(){
\n List<Integer> list = new ArrayList<>();
\n list.add(4);
\n list.add(5);
\n list.add(9);
\n List<Users> users = mapper.selIn(list);
\n for (Users user : users) {
\n System.out.println(user);
\n }
\n }<\/p>\n
@Test
\n public void selChose(){
\n List<Users> users = mapper.selChose();
\n for (Users user : users) {
\n System.out.println(user);
\n }
\n }
\n} <\/p>\n
1.\u7f13\u5b58\u5c31\u662f\u7528\u6237\u5728\u7b2c\u4e00\u6b21\u8bbf\u95ee\u67d0\u4e9b\u6570\u636e\u7684\u65f6\u5019，\u4f1a\u5c06\u8fd9\u4e9b\u6570\u636e\u7f13\u5b58\u5230redis\u4e2d，\u5982\u679c\u8981\u518d\u6b21\u8bbf\u95ee\u8fd9\u4e9b\u5185\u5bb9，\u53ef\u4ee5\u76f4\u63a5\u4eceredis\u4e2d\u8bfb\u53d6，\u800c\u4e0d\u9700\u8981\u5728\u53bb\u8bbf\u95ee\u6570\u636e\u5e93\u4e86\u3002<\/p>\n
2.redis\u53ef\u4ee5\u770b\u4f5c\u662f\u4e00\u4e2a\u57fa\u4e8e\u5185\u5b58\u7684\u6570\u636e\u5e93，\u800cmysql\u53ef\u4ee5\u770b\u4f5c\u662f\u57fa\u4e8e\u786c\u76d8\u7684\u6570\u636e\u5e93\u3002<\/p>\n
3.\u7f13\u5b58\u7684\u4f5c\u7528：<\/p>\n
（1）\u7f13\u5b58\u7528\u4e8e\u63d0\u9ad8\u67e5\u8be2\u7684\u6548\u7387\u3002<\/p>\n
（2）MyBatis\u7684\u7f13\u5b58\u662f\u4f7f\u7528SQL\u6807\u7b7e\u7684ID\u4f5c\u4e3a\u7f13\u5b58\u7684\u552f\u4e00\u6807\u8bc6\u7684，\u6267\u884c\u76f8\u540c\u7684\u6807\u7b7e\u53ef\u4ee5\u4f7f\u7528\u7f13\u5b58，\u4e0d\u540c\u7684\u6807\u7b7e\u4e0d\u80fd\u4f7f\u7528\u7f13\u5b58\u3002<\/p>\n
（3）MyBatis\u4e2d\u6709\u4e24\u79cd\u7f13\u5b58\u673a\u5236，\u4e00\u4e2a\u662f\u4e00\u7ea7\u7f13\u5b58，\u4e00\u4e2a\u662f\u4e8c\u7ea7\u7f13\u5b58\u3002<\/p>\n
4.\u4e00\u7ea7\u7f13\u5b58：<\/p>\n
（1）\u9ed8\u8ba4\u5f00\u542f\u7ebf\u7a0b\u7ea7\u522b\u7684\u7f13\u5b58，SqlSession\u7684\u7f13\u5b58\u3002<\/p>\n
（2）\u5728\u4e00\u4e2aSqlSession\u751f\u547d\u5468\u671f\u4e2d\u6709\u6548，SqlSession\u5173\u95ed，\u7f13\u5b58\u6e05\u7a7a\u3002<\/p>\n
5.\u4e8c\u7ea7\u7f13\u5b58：<\/p>\n
（1）\u8fdb\u7a0b\u7ea7\u522b\u7684\u7f13\u5b58，SqlSessionFactory\u7684\u7f13\u5b58\u3002<\/p>\n
（2）\u5728\u4e00\u4e2aSqlSessionFactory\u751f\u547d\u5468\u671f\u4e2d\u6709\u6548，\u53ef\u4ee5\u5728\u591a\u4e2aSqlSession\u751f\u547d\u5468\u671f\u4e2d\u5171\u4eab\u3002<\/p>\n
（3）\u9ed8\u8ba4\u5173\u95ed，\u9700\u8981\u4f7f\u7528\u7684\u65f6\u5019，\u8981\u4e3a\u67d0\u4e2a\u547d\u540d\u7a7a\u95f4\u5f00\u542f\u4e8c\u7ea7\u7f13\u5b58(\u5728mapper.xml\u4e2d\u914d\u7f6e<cache>)：<\/p>\n
1.\u5982\u679c\u67e5\u8be2\u65f6\u4f7f\u7528resultType\u5c5e\u6027，\u8868\u793a\u91c7\u7528MyBatis\u7684Auto-Mapping(\u81ea\u52a8\u6620\u5c04)\u673a\u5236，\u5373\u76f8\u540c\u7684\u5217\u540d\u548c\u5c5e\u6027\u540d\u4f1a\u81ea\u52a8\u5339\u914d\u3002\u56e0\u6b64，\u5f53\u6570\u636e\u5e93\u8868\u7684\u5217\u540d\u548c\u7c7b\u7684\u5c5e\u6027\u540d\u4e0d\u4e00\u81f4\u65f6，\u4f1a\u5bfc\u81f4\u67e5\u4e0d\u5230\u6570\u636e\u3002\u89e3\u51b3\u8be5\u95ee\u9898\u6709\u4e24\u79cd\u65b9\u5f0f：\u4e00\u79cd\u662f\u5217\u522b\u540d，\u4e00\u79cd\u662f\u4f7f\u7528resultMap\u624b\u52a8\u6620\u5c04\u3002<\/p>\n
2.\u5217\u522b\u540d：<\/p>\n
（1）\u67e5\u8be2\u65f6，\u53ef\u4ee5\u901a\u8fc7\u5217\u522b\u540d\u7684\u65b9\u5f0f\u5c06\u5217\u540d\u548c\u5c5e\u6027\u540d\u4fdd\u6301\u4e00\u81f4，\u7ee7\u7eed\u4f7f\u7528\u81ea\u52a8\u6620\u5c04，\u4ece\u800c\u89e3\u51b3\u8be5\u95ee\u9898，\u4f46\u662f\u8f83\u4e3a\u9ebb\u70e6\u3002<\/p>\n
3.resultMap\u624b\u52a8\u6620\u5c04：<\/p>\n
（1）\u5c06resultType\u6362\u6210resultMap<\/p>\n
（2）\u5728sql\u8bed\u53e5\u5bf9\u5e94\u7684\u6807\u7b7e\u5916\u9762\u52a0\u4e00\u4e2aresultMap\u6807\u7b7e\u3002<\/p>\n
（3）\u683c\u5f0f：<\/p>\n
1.\u591a\u8868\u5173\u8054\u67e5\u8be2\u5728MyBatis\u4e2d\u53ef\u4ee5\u6709\u4e24\u79cd\u65b9\u5f0f\u5b9e\u73b0：\u4e00\u79cd\u662f\u5173\u8054\u7684\u65b9\u5f0f，\u4e00\u79cd\u662f\u88c5\u914d\u7684\u65b9\u5f0f\u3002<\/p>\n
2.\u5173\u8054\u5b9e\u73b0\u591a\u8868\u67e5\u8be2：<\/p>\n
（1）\u5173\u8054\u7684\u65b9\u5f0f\u5c31\u662f\u5c06sql\u8bed\u53e5\u5b8c\u6574\u7684\u653e\u5165\u6620\u5c04\u6587\u4ef6\u4e2d，\u7136\u540e\u52a8\u6001\u53d6\u503c\u67e5\u8be2\u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n
3.\u624b\u52a8\u88c5\u914d\u5b9e\u73b0\u591a\u8868\u67e5\u8be2(\u591a\u5bf9\u4e00)：<\/p>\n
（1）mapper\u5c42\u53ea\u505a\u5355\u8868\u67e5\u8be2\u64cd\u4f5c，\u5728service\u5c42\u8fdb\u884c\u624b\u52a8\u88c5\u914d，\u5b9e\u73b0\u5173\u8054\u67e5\u8be2\u7684\u7ed3\u679c\u3002<\/p>\n
（2）\u5728application\u4e2d\u5173\u8054\u6620\u5c04\u6587\u4ef6\u7684\u65f6\u5019，\u5982\u679c\u6709\u591a\u4e2a\u6620\u5c04\u6587\u4ef6，\u4e00\u4e2a\u4e00\u4e2a\u5173\u8054\u592a\u9ebb\u70e6\u4e86，\u53ef\u4ee5\u4f7f\u7528<package>\u6807\u7b7e：<\/p>\n
（3）\u624b\u52a8\u88c5\u914d\u5c31\u662f\u5148\u5c06\u4e00\u4e2a\u8868\u4e2d\u7684\u6570\u636e\u67e5\u5904\u7406，\u5728\u6839\u636e\u8fd9\u4e2a\u8868\u4e2d\u5173\u8054\u7684\u5916\u952e\u53bb\u67e5\u8be2\u53e6\u4e00\u5f20\u8868\u4e2d\u7684\u5185\u5bb9，\u8fd9\u6837\u4e24\u5f20\u8868\u4e2d\u7684\u5185\u5bb9\u5c31\u90fd\u67e5\u5230\u4e86\u3002<\/p>\n
（4）\u624b\u52a8\u88c5\u914d\u5176\u5b9e\u5c31\u662f\u628a\u591a\u8868\u67e5\u8be2\u62c6\u5206\u6210\u5355\u8868\u67e5\u8be2\u3002\u5982\u679c\u662f\u591a\u5bf9\u4e00\u67e5\u8be2，\u5c31\u5148\u628a\u591a\u7684\u4e00\u65b9\u67e5\u51fa\u6765，\u5728\u7528\u591a\u628a\u4e00\u67e5\u51fa\u6765\u3002\u5982\u679c\u662f\u4e00\u5bf9\u591a，\u5c31\u5148\u628a\u4e00\u67e5\u51fa\u6765，\u518d\u53bb\u67e5\u8be2\u591a\u3002<\/p>\n
（5）\u7b80\u5355\u6765\u8bf4，\u624b\u52a8\u88c5\u914d\u53ef\u4ee5\u7406\u89e3\u4e3a\u624b\u52a8\u7ec4\u88c5，\u628a\u4f60\u8981\u7684\u591a\u4e2a\u5173\u8054\u8d77\u6765\u7684\u6570\u636e\u5148\u62c6\u5206\u6210\u5355\u4e2a\u6570\u636e\u8fdb\u884c\u67e5\u8be2，\u6700\u540e\u5c06\u67e5\u8be2\u7684\u7ed3\u679c\u5728\u624b\u52a8\u7ec4\u88c5\u8d77\u6765，\u8fd9\u4e2a\u79f0\u4e4b\u4e3a\u4e1a\u52a1\u88c5\u914d\u3002<\/p>\n
（6）\u6ce8\u610f：\u8fd9\u79cd\u5173\u8054\u67e5\u8be2\u9700\u8981\u6211\u4eec\u5728\u5b9e\u4f53\u7c7b\u4e2d\u5c06\u6570\u636e\u5173\u8054\u8d77\u6765，\u6bd4\u5982\u591a\u5bf9\u4e00，\u90a3\u4e48\u6211\u4eec\u5c31\u8981\u4f7f\u7528\u591a\u53bb\u6301\u6709\u4e00，\u5c31\u50cf\u591a\u4e2a\u5b66\u751f\u5bf9\u5e94\u4e00\u4e2a\u73ed\u7ea7，\u90a3\u4e48\u6211\u4eec\u5c31\u8981\u5c06\u73ed\u7ea7\u7684\u5b9e\u4f53\u7c7b\u5f53\u4f5c\u5b66\u751f\u7684\u5b9e\u4f53\u7c7b\u662f\u5c5e\u6027\u3002<\/p>\n
（7）\u6848\u4f8b：<\/p>\n
import com.mybatis.pojo.Clazz;<\/p>\n
public interface ClazzMapper {
\n Clazz selByCid(int cid);
\n} <\/li>\n
import com.mybatis.pojo.Student;<\/p>\n
import java.util.List;<\/p>\n
public interface StudentMapper {
\n List<Student> selAll();
\n} <\/li>\n
import com.mybatis.mapper.ClazzMapper;
\nimport com.mybatis.mapper.StudentMapper;
\nimport com.mybatis.pojo.Clazz;
\nimport com.mybatis.pojo.Student;
\nimport org.apache.ibatis.io.Resources;
\nimport org.apache.ibatis.session.SqlSession;
\nimport org.apache.ibatis.session.SqlSessionFactory;
\nimport org.apache.ibatis.session.SqlSessionFactoryBuilder;
\nimport org.junit.Test;<\/p>\n
import java.io.IOException;
\nimport java.io.InputStream;
\nimport java.util.List;<\/p>\n
public class Demo {
\n SqlSession session;
\n ClazzMapper clazzMapper;
\n StudentMapper studentMapper;
\n public Demo(){
\n \/\/\u52a0\u8f7dapplication-dao.xml
\n String resource = "application-dao.xml";
\n try {
\n \/\/\u5c06\u6587\u4ef6\u8f6c\u6362\u4e3a\u6d41\u5bf9\u8c61
\n InputStream resourceAsStream = Resources.getResourceAsStream(resource);
\n \/\/\u83b7\u53d6SqlSessionFactory\u5bf9\u8c61
\n SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
\n \/\/\u83b7\u53d6\u53d1\u9001sql\u8bed\u53e5\u7684\u5bf9\u8c61
\n session = sqlSessionFactory.openSession();
\n \/\/\u83b7\u53d6\u63a5\u53e3\u5bf9\u8c61
\n clazzMapper = this.session.getMapper(ClazzMapper.class);
\n studentMapper = this.session.getMapper(StudentMapper.class);
\n } catch (IOException e) {
\n e.printStackTrace();
\n }
\n }<\/p>\n
\/**
\n * \u67e5\u8be2\u5b66\u751f\u53ca\u5176\u6240\u5728\u7684\u73ed\u7ea7\u4fe1\u606f(\u591a\u5bf9\u4e00 \u67e5\u8be2)
\n * \u624b\u52a8\u88c5\u914d
\n *\/
\n @Test
\n public void selAll(){
\n List<Student> students = studentMapper.selAll();
\n for (Student stu : students) {
\n \/\/\u5b66\u751f\u5bf9\u5e94\u7684\u73ed\u7ea7cid
\n int cid = stu.getCid();
\n \/\/\u6839\u636ecid\u67e5\u8be2\u5b83\u6240\u5728\u7684\u73ed\u7ea7
\n Clazz clazz = clazzMapper.selByCid(cid);
\n stu.setClazz(clazz);
\n }
\n for (Student stu : students) {
\n System.out.println(stu.getSid() + "-" + stu.getSname() + "-" + stu.getAge() + "-" + stu.getCid() + "-" + stu.getClazz());
\n }
\n }
\n} <\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
\u76ee\u5f55 \u4e00\u3001\u52a8\u6001sql(\u63a5SSM\u6846\u67b6-MyBatis2\u4e2d\u7684\u52a8\u6001sql)
\n\u4e8c\u3001MyBatis\u7684\u7f13\u5b58\u673a\u5236
\n\u4e09\u3001\u6570\u636e\u5e93\u4e2d\u5217\u540d\u548cpojo\u4e2d\u7684\u5b9e\u4f53\u7c7b\u4e0d\u4e00\u81f4\u95ee\u9898
\n\u56db\u3001\u591a\u8868\u5173\u8054\u67e5\u8be2 \u4e00\u3001\u52a8\u6001sql(\u63a5SSM\u6846\u67b6-MyBatis2\u4e2d\u7684\u52a8\u6001sql)
\n1.\u6807\u7b7e：
\n（1）\u5355\u6761\u4ef6\u67e5\u8be2(\u53ea\u53d6\u5176\u4e00)，\u8fd9\u662f\u4e00\u5957\u6807\u7b7e，\u529f\u80fd\u7c7b\u4f3c\u4e8eif…else if…else if…el<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[99,190,305],"topic":[],"class_list":["post-78292","post","type-post","status-publish","format-standard","hentry","category-server","tag-java","tag-190","tag-305"],"yoast_head":"\n