10、mybatis学习——sqlmapper配置返回list和map结果集

目录

• 一、返回list
• 二、查询一个记录返回一个map
• 三、查询多条记录返回一个map

 

---

回到顶部

一、返回list

　　mapper接口方法：

　　sqlmapper文件配置：

    <!-- 根据name模糊查询返回list
            resultType写list里面的类型，多个结果mybatis会自动添加到list中 -->
    <select id="selectEmpByNameLike" resultType="employee">
        select * from employee where name like #{name}
    </select>

　　测试方法：

    @Test
    public void testSelectEmpByNameLike() throws IOException {
        String source = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(source);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        EmployeeMapper employeeMapper = sqlSession.getMapper(EmployeeMapper.class);
        System.out.println(employeeMapper.selectEmpByNameLike("%o%"));
        sqlSession.close();
    }

回到顶部

二、查询一个记录返回一个map

　　mapper接口方法：

 　　sqlmapper文件配置

    <!-- 返回一条记录的map；key就是列名，值就是对应列的值
        查询结果只有一条时resultType的值为map，mybatis自动为许多java类型取了别名 -->
    <select id="selectEmpByIdReturnMap" resultType="map">
        select * from employee where id = #{id}
    </select>

　　测试方法：

    @Test
    public void testSelectEmpByIdReturnMap() throws IOException {
        String source = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(source);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        
        SqlSession sqlSession = sqlSessionFactory.openSession();
        
        EmployeeMapper employeeMapper = sqlSession.getMapper(EmployeeMapper.class);
        System.out.println(employeeMapper.selectEmpByIdReturnMap(1));
        sqlSession.close();
    }

回到顶部

三、查询多条记录返回一个map

　　mapper接口方法：

 　　sqlmapper文件配置：

    <!-- 返回多条记录的map；key为对应map接口方法中的@MapKey的值，值就是对应key的对象
    查询结果为多条时resultType的值为返回对象的类型 -->
    <select id="selectEmpByNameLikeReturnMap" resultType="employee">
        select * from employee where name like #{name}
    </select>

　　测试方法：

    @Test
    public void testSelectEmpByNameLikeReturnMap() throws IOException {
        String source = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(source);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        
        SqlSession sqlSession = sqlSessionFactory.openSession();
        
        EmployeeMapper employeeMapper = sqlSession.getMapper(EmployeeMapper.class);
        System.out.println(employeeMapper.selectEmpByNameLikeReturnMap("%o%"));
        sqlSession.close();
    }