mybatis的mapper代理，SqlMapConfig.xml中配置，输入和输出映射使用案例

public class User {
    private int id;
    private String username;// 用户姓名
    private String sex;// 性别
    private Date birthday;// 生日
    private String address;// 地址
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", username=" + username + ", sex=" + sex
                + ", birthday=" + birthday + ", address=" + address + "]";
    }
}

public class UserCustom extends User {
    //添加一些扩展字段
}

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;
    }
}

<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <properties resource="db.properties"></properties>
    <!-- 定义 别名 -->
    <typeAliases>
        <!--
            单个别名的定义
            alias：别名，type：别名映射的类型  -->
            <!-- <typeAlias type="cn.itcast.mybatis.po.User" alias="user"/> -->
            <!-- 批量别名定义
            指定包路径，自动扫描包下边的pojo，定义别名，别名默认为类名（首字母小写或大写）
         -->
        <package name="cn.itcast.mybatis.po"/>
    </typeAliases>
    <!-- 和spring整合后 environments配置将废除-->
    <environments default="development">
        <environment id="development">
        <!-- 使用jdbc事务管理-->
            <transactionManager type="JDBC" />
        <!-- 数据库连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>
    <!--加载mapper映射
    如果将和spring整合后，可以使用整合包中提供的mapper扫描器，此处的mappers不用配置了。
     -->
    <mappers>
        <package name="cn.yzu.mybatis.mapper"/>
    </mappers>
</configuration>

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">
<!-- namespace命名空间，为了对sql语句进行隔离，方便管理 ，mapper开发dao方式，使用namespace有特殊作用
mapper代理开发时将namespace指定为mapper接口的全限定名
 -->
<mapper namespace="cn.yzu.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
       -->
     <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 '%${userCustom.username}%'
                </if>
                <if test="userCustom.sex!=null and userCustom.sex!=''">
                    and sex = #{userCustom.sex}
                </if>
                <!-- 根据id集合查询用户信息 -->
                <!-- 最终拼接的效果：
                SELECT id ,username ,birthday  FROM USER WHERE username LIKE '%小明%' AND id IN (16,22,25)
                collection：集合的属性
                open：开始循环拼接的串
                close：结束循环拼接的串
                item：每次循环取到的对象
                separator：每两次循环中间拼接的串
                 -->
                 <foreach collection="ids" open=" AND id IN ( " close=")" item="id" separator=",">
                     #{id}
                 </foreach>
                 <!-- 
                 SELECT id ,username ,birthday  FROM USER WHERE username LIKE '%小明%' AND (id = 16 OR id = 22 OR id = 25) 
                  <foreach collection="ids" open=" AND ( " close=")" item="id" separator="OR">
                     id = #{id}
                 </foreach>
                  -->
                <!-- 还有很多的查询条件 -->
            </if>
     </sql>
     <!-- 定义resultMap，列名和属性名映射配置
     id：mapper.xml中的唯一标识 
     type：最终要映射的pojo类型
      -->
     <resultMap id="userListResultMap" type="user" >
         <!-- 列名
         id_,username_,birthday_
         id：要映射结果集的唯 一标识 ，称为主键
         column：结果集的列名
         property：type指定的哪个属性中
          -->
          <id column="id_" property="id"/>
          <!-- result就是普通列的映射配置 -->
          <result column="username_" property="username"/>
          <result column="birthday_" property="birthday"/>
     </resultMap>
    <!-- 根据id查询用户信息 -->
    <select id="findUserById" parameterType="int" resultType="user">
        SELECT * FROM USER WHERE id= #{id}
    </select>
    <!-- 根据用户名称查询用户信息，可能返回多条-->
    <select id="findUserByName" parameterType="java.lang.String" resultType="cn.yzu.mybatis.po.User">
        select * from user where username like '%${value}%'
    </select>
    <!-- 自定义查询条件查询用户的信息
    %${userCustom.username}%：userCustom是userQueryVo中的属性，通过OGNL获取属性的值
     -->
    <select id="findUserList" parameterType="userQueryVo" resultType="user">
        select id,username,birthday,sex from user
        <!-- where标签相当 于where关键字，可以自动去除第一个and -->
        <where>
            <!-- 引用sql片段，如果sql片段和引用处不在同一个mapper必须前边加namespace -->
            <include refid="query_user_where"></include>
            <!-- 下边还有很其它的条件 -->
            <!-- <include refid="其它的sql片段"></include> -->
        </where>
    </select>
    <!-- 使用resultMap作结果映射
    resultMap：如果引用resultMap的位置和resultMap的定义在同一个mapper.xml，直接使用resultMap的id，如果不在同一个mapper.xml要在resultMap的id前边加namespace
     -->
    <select id="findUserListResultMap" parameterType="userQueryVo" resultMap="userListResultMap">
        select id id_,username username_,birthday birthday_ from user where username like '%${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>
            <include refid="query_user_where"></include>
        </where>
     </select>
    <!-- 添加用户-->
    <insert id="insertUser" parameterType="cn.yzu.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>
</mapper>

public class UserMapperTest {
    // 会话工厂
    private SqlSessionFactory sqlSessionFactory;
    // 创建工厂
    @Before
    public void init() throws IOException {
        String resource = "SqlMapConfig.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    }
    @Test
    public void testFindUserById() throws Exception {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        // 创建代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.findUserById(1);
        System.out.println(user);
    }
    @Test
    public void testFindUserByUsername() throws Exception {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> list = userMapper.findUserByName("小明");
        System.out.println(list);
    }
    @Test
    public void testInsertUser() throws Exception {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setUsername("李奎123");
        userMapper.insertUser(user);
        sqlSession.commit();
        sqlSession.close();
    }
    // 通过包装类型查询用户信息
    @Test
    public void testFindUserList() throws Exception {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        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 
    @Test
    public void testFindUserListResultMap() throws Exception {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        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
    @Test
    public void testFindUserCount() throws Exception {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        UserQueryVo userQueryVo = new UserQueryVo();
        UserCustom userCustom = new UserCustom();
        userCustom.setUsername("小明");
        userQueryVo.setUserCustom(userCustom);
        //id集合
        List<Integer> ids  = new ArrayList<Integer>();
        ids.add(16);
        ids.add(22);
        userQueryVo.setIds(ids);
        int count = userMapper.findUserCount(userQueryVo);
        sqlSession.close();
        System.out.println(count);
    }
}