package cn.itcast.mybatis.mapper;import java.util.List;import cn.itcast.mybatis.po.User;
import cn.itcast.mybatis.po.UserQueryVo;public interface UserMapper {//根据用户id查询用户信息public User findUserById(int id) throws Exception;//根据用户名称  查询用户信息public List<User> findUserByName(String username) throws Exception;//自定义查询条件查询用户信息public List<User> findUserList(UserQueryVo userQueryVo) throws Exception;//查询用户，使用resultMap进行映射public List<User> findUserListResultMap(UserQueryVo userQueryVo)throws Exception;//查询用户，返回记录个数public int findUserCount(UserQueryVo userQueryVo) throws Exception;//插入用户public void insertUser(User user)throws Exception;//删除用户public void deleteUser(int id) throws Exception;//修改用户public void updateUser(User user) throws Exception;}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--mapper代理开发时将namespace指定为mapper接口的全限定名-->
<mapper namespace="cn.itcast.mybatis.mapper.UserMapper">
<!-- 在mapper.xml文件中配置很多的sql语句，执行每个sql语句时，封装为MappedStatement对象
mapper.xml以statement为单位管理sql语句--><!-- 将用户查询条件定义为sql片段建议对单表的查询条件单独抽取sql片段，提高公用性注意：不要将where标签放在sql片段（公用性差）--><sql id="query_user_where"><!-- 如果 userQueryVo中传入查询条件，再进行sql拼接--><!-- test中userCustom.username表示从userQueryVo读取属性值--><if test="userCustom!=null"><if test="userCustom.username!=null and userCustom.username!=''">and username like '%${userCustom.username}%'</if><if test="userCustom.sex!=null and userCustom.sex!=''">and sex = #{userCustom.sex}</if><!-- 根据id集合查询用户信息 --><!-- 最终拼接的效果：SELECT id ,username ,birthday  FROM USER WHERE username LIKE '%小明%'       AND id IN (开始          16,22,25循环             )结束collection：集合的属性，userQueryVo的ids属性open：开始循环拼接的串close：结束循环拼接的串item：每次循环取到的对象separator：每两次循环中间拼接的串--><foreach collection="ids" open=" AND id IN ( " close=")" item="id" separator=",">#{id}    <!-- 16，循环 --></foreach><!-- 如果拼接 SELECT id ,username ,birthday  FROM USER WHERE username LIKE '%小明%' AND (开始                id = 16 OR id = 22 OR id = 25循环             )结束 <foreach collection="ids" open=" AND ( " close=")" item="id" separator="OR">id = #{id}   <!--  id = 16 ，循环 --></foreach>--><!-- 还有很的查询条件 --></if></sql><!-- 定义resultMap，列名和属性名映射配置id：mapper.xml中的唯一标识 type：最终要映射的pojo类型--><resultMap id="userListResultMap" type="user" ><!-- 列名id_,username_,birthday_id：要映射结果集（查询的结果select id id_,username username_,birthday birthday_）的唯 一标识 ，称为主键column：结果集（查询的结果）的列名property：type指定的哪个属性中--><id column="id_" property="id"/><!-- result就是普通列的映射配置 --><result column="username_" property="username"/><result column="birthday_" property="birthday"/></resultMap><!-- 根据id查询用户信息 --><!-- id：唯一标识 一个statement#{}：表示 一个占位符，如果#{}中传入简单类型的参数，#{}中的名称随意parameterType：输入 参数的类型，通过#{}接收parameterType输入 的参数resultType：输出结果 类型，不管返回是多条还是单条，指定单条记录映射的pojo类型--><select id="findUserById" parameterType="int" resultType="user">SELECT * FROM USER WHERE id= #{id}</select><!-- 根据用户名称查询用户信息，可能返回多条${}：表示sql的拼接，通过${}接收参数，将参数的内容不加任何修饰拼接在sql中。--><select id="findUserByName" parameterType="java.lang.String" resultType="cn.itcast.mybatis.po.User">select * from user where username like '%${value}%'</select><!-- 自定义查询条件查询用户的信息parameterType：指定包装类型%${userCustom.username}%：userCustom是userQueryVo中的属性，通过OGNL获取属性的值--><select id="findUserList" parameterType="userQueryVo" resultType="user">select id,username,birthday from user<!-- where标签相当 于where关键字，可以自动去除第一个and --><where><!-- 引用sql片段，如果sql片段和引用处不在同一个mapper必须前边加namespace --><include refid="query_user_where"></include><!-- 下边还有很其它的条件 --><!-- <include refid="其它的sql片段"></include> --></where></select><!-- 使用resultMap作结果映射resultMap：如果引用resultMap的位置和resultMap的定义在同一个mapper.xml，直接使用resultMap的id，如果不在同一个mapper.xml要在resultMap的id前边加namespace--><select id="findUserListResultMap" parameterType="userQueryVo" resultMap="userListResultMap">select id id_,username username_,birthday birthday_ from user where username like '%${userCustom.username}%'</select><!-- 输出简单类型功能：自定义查询条件，返回查询记录个数，通常用于实现 查询分页--><select id="findUserCount" parameterType="userQueryVo" resultType="int">select count(*) from user <!-- where标签相当 于where关键字，可以自动去除第一个and --><where><!-- 引用sql片段，如果sql片段和引用处不在同一个mapper必须前边加namespace --><include refid="query_user_where"></include><!-- 下边还有很其它的条件 --><!-- <include refid="其它的sql片段"></include> --></where></select><!-- 添加用户parameterType：输入 参数的类型，User对象 包括 username,birthday,sex,address#{}接收pojo数据，可以使用OGNL解析出pojo的属性值#{username}表示从parameterType中获取pojo的属性值selectKey：用于进行主键返回，定义了获取主键值的sqlorder：设置selectKey中sql执行的顺序，相对于insert语句来说keyProperty：将主键值设置到哪个属性resultType：select LAST_INSERT_ID()的结果 类型--><insert id="insertUser" parameterType="cn.itcast.mybatis.po.User"><selectKey keyProperty="id" order="AFTER" resultType="int">select LAST_INSERT_ID()</selectKey>INSERT INTO USER(username,birthday,sex,address) VALUES(#{username},#{birthday},#{sex},#{address})</insert><!-- mysql的uuid生成主键 --><!-- <insert id="insertUser" parameterType="cn.itcast.mybatis.po.User"><selectKey keyProperty="id" order="BEFORE" resultType="string">select uuid()</selectKey>INSERT INTO USER(id,username,birthday,sex,address) VALUES(#{id},#{username},#{birthday},#{sex},#{address})</insert> --><!-- oracle在执行insert之前执行select 序列.nextval() from dual取出序列最大值，将值设置到user对象 的id属性--><!-- <insert id="insertUser" parameterType="cn.itcast.mybatis.po.User"><selectKey keyProperty="id" order="BEFORE" resultType="int">select 序列.nextval() from dual</selectKey>INSERT INTO USER(id,username,birthday,sex,address) VALUES(#{id},#{username},#{birthday},#{sex},#{address})</insert> --><!-- 用户删除  --><delete id="deleteUser" parameterType="int">delete from user where id=#{id}</delete><!-- 用户更新 要求：传入的user对象中包括 id属性值--><update id="updateUser" parameterType="cn.itcast.mybatis.po.User">update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id}</update></mapper>

package cn.itcast.mybatis.mapper;import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;import cn.itcast.mybatis.po.User;
import cn.itcast.mybatis.po.UserCustom;
import cn.itcast.mybatis.po.UserQueryVo;public class UserMapperTest {// 会话工厂private SqlSessionFactory sqlSessionFactory;// 创建工厂@Beforepublic void init() throws IOException {// 配置文件（SqlMapConfig.xml）String resource = "SqlMapConfig.xml";// 加载配置文件到输入 流InputStream inputStream = Resources.getResourceAsStream(resource);// 创建会话工厂sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);}@Testpublic void testFindUserById() throws Exception {SqlSession sqlSession = sqlSessionFactory.openSession();// 创建代理对象，接口实现类UserMapper userMapper = sqlSession.getMapper(UserMapper.class);User user = userMapper.findUserById(1);System.out.println(user);}@Testpublic void testFindUserByUsername() throws Exception {SqlSession sqlSession = sqlSessionFactory.openSession();// 创建代理对象，接口实现类UserMapper userMapper = sqlSession.getMapper(UserMapper.class);List<User> list = userMapper.findUserByName("小明");System.out.println(list);}@Testpublic void testInsertUser() throws Exception {SqlSession sqlSession = sqlSessionFactory.openSession();// 创建代理对象，接口实现类UserMapper userMapper = sqlSession.getMapper(UserMapper.class);// 插入对象User user = new User();user.setUsername("李奎");userMapper.insertUser(user);sqlSession.commit();sqlSession.close();}// 通过包装类型查询用户信息@Testpublic void testFindUserList() throws Exception {SqlSession sqlSession = sqlSessionFactory.openSession();// 创建代理对象，接口实现类UserMapper userMapper = sqlSession.getMapper(UserMapper.class);// 构造查询条件UserQueryVo userQueryVo = new UserQueryVo();UserCustom userCustom = new UserCustom();userCustom.setUsername("小明");userCustom.setSex("1");userQueryVo.setUserCustom(userCustom);//id集合List<Integer> ids  = new ArrayList<Integer>();ids.add(16);ids.add(22);userQueryVo.setIds(ids);List<User> list = userMapper.findUserList(userQueryVo);sqlSession.close();System.out.println(list);}// 使用resultMap进行结果映射 @Testpublic void testFindUserListResultMap() throws Exception {SqlSession sqlSession = sqlSessionFactory.openSession();// 创建代理对象，接口实现类UserMapper userMapper = sqlSession.getMapper(UserMapper.class);// 构造查询条件UserQueryVo userQueryVo = new UserQueryVo();UserCustom userCustom = new UserCustom();userCustom.setUsername("小明");userQueryVo.setUserCustom(userCustom);List<User> list = userMapper.findUserListResultMap(userQueryVo);sqlSession.close();System.out.println(list);}// 返回查询记录总数@Testpublic void testFindUserCount() throws Exception {SqlSession sqlSession = sqlSessionFactory.openSession();// 创建代理对象，接口实现类UserMapper userMapper = sqlSession.getMapper(UserMapper.class);// 构造查询条件UserQueryVo userQueryVo = new UserQueryVo();UserCustom userCustom = new UserCustom();userCustom.setUsername("小明");userQueryVo.setUserCustom(userCustom);int count = userMapper.findUserCount(userQueryVo);sqlSession.close();System.out.println(count);}}

package cn.itcast.mybatis.po;import java.util.List;/**
包装类型，将来在使用时从页面传到controller、service、mapper </p>*/
public class UserQueryVo {//用户信息private User user;//自定义user的扩展对象private UserCustom userCustom;//用户id集合private List<Integer> ids;public User getUser() {return user;}public void setUser(User user) {this.user = user;}public UserCustom getUserCustom() {return userCustom;}public void setUserCustom(UserCustom userCustom) {this.userCustom = userCustom;}public List<Integer> getIds() {return ids;}public void setIds(List<Integer> ids) {this.ids = ids;}}