开始

1. 在接口中加入方法

public Proper getByProperId(@Param("id") int id);

2.在mapper配置文件中编写对应的标签

<resultMap id="proper" type="com.example.mybatis.Proper">
        <id property="id" column="p_id"/>
        <id property="name" column="p_name"/>
        <id property="meg" column="p_meg"/>
        <collection property="home" ofType="com.example.mybatis.Home">
            <id property="id" column="h_id"/>
            <id property="name" column="h_name"/>
        </collection>
    </resultMap>
    <select id="getByProperId" resultMap="proper" parameterType="_int">
        select h.id as h_id,
               h.name as h_name,
               p.name as p_name,
               p.id as p_id,
               p.meg as p_meg
        from proper p join home h on p.id = h.master
        where p.id=#{id}
    </select>

3. 测试

SqlSessionFactory sqlSessionFactory=SessionFactory.getSessionFactory();
		try (SqlSession sqlSession=sqlSessionFactory.openSession()){
			t1Mapper mapper = sqlSession.getMapper(t1Mapper.class);
			Proper byProperId = mapper.getByProperId(1);
			System.out.println(byProperId.toString());
		}

注意

• 对象中的list用collection标签
• 在collection中用ofType指定类型