mybatis查询返回多条数据

返回User类型的list

<select id="queryAllUser" resultType="org.example.entity.User">
        select * from t_user
</select>

public interface UserMapper {

    public void addUser();

    public List<User> queryAllUser();

    public User queryUserByid(@Param("name") String name);
}

@Test
    public void queryAllUser(){
        SqlSession sqlSession = SqlSessionUtil.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> users = mapper.queryAllUser();
        System.out.println(users);
    }

 

查询所有用户信息为map集合（方法1）

    <select id="queryAllUser" resultType="map">
        select * from t_user
    </select>

public interface UserMapper {

    public void addUser();

    public User queryUserByid(@Param("name") String name);

    public List<Map<String, Object>> queryAllUser();

}

@Test
    public void queryAllUser(){
        SqlSession sqlSession = SqlSessionUtil.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<Map<String, Object>> maps = mapper.queryAllUser();
        System.out.println(maps);
    }

[{gender=男, name=tom, id=1, age=20, email=123123@qq.com}, {gender=女, name=luccy, id=2, age=10, email=22222@qq.com}]

 

查询所有用户信息为map集合（方法2）

 <select id="queryAllUser" resultType="map">
        select * from t_user
 </select>

public interface UserMapper {

    public void addUser();

    public User queryUserByid(@Param("name") String name);

    @MapKey("id")//设置id为map集合的key
    public Map<String, Object> queryAllUser();

}

 @Test
    public void queryAllUser(){
        SqlSession sqlSession = SqlSessionUtil.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        Map<String, Object> maps = mapper.queryAllUser();
        System.out.println(maps);
    }

{1={gender=男, name=tom, id=1, age=20, email=123123@qq.com}, 2={gender=女, name=luccy, id=2, age=10, email=22222@qq.com}}