10、mybatis學習——sqlmapper配置返回list和map結果集

一、返回list

　　mapper接口方法：

　　sqlmapper文件配置：

    <!-- 根據name模糊查詢返回list
            resultType寫list里面的類型，多個結果mybatis會自動添加到list中 -->
    <select id="selectEmpByNameLike" resultType="employee">
        select * from employee where name like #{name}
    </select>

　　測試方法：

    @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();
    }

二、查詢一個記錄返回一個map

　　mapper接口方法：

 　　sqlmapper文件配置

    <!-- 返回一條記錄的map；key就是列名，值就是對應列的值
        查詢結果只有一條時resultType的值為map，mybatis自動為許多java類型取了別名 -->
    <select id="selectEmpByIdReturnMap" resultType="map">
        select * from employee where id = #{id}
    </select>

　　測試方法：

    @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();
    }

三、查詢多條記錄返回一個map

　　mapper接口方法：

 　　sqlmapper文件配置：

    <!-- 返回多條記錄的map；key為對應map接口方法中的@MapKey的值，值就是對應key的對象
    查詢結果為多條時resultType的值為返回對象的類型 -->
    <select id="selectEmpByNameLikeReturnMap" resultType="employee">
        select * from employee where name like #{name}
    </select>

　　測試方法：

    @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();
    }