mybatis中session.getMapper()方法和resultMap

Posted 2020-10-09 努力奋斗吧

session.getMapper()方法的使用：

定义接口

  /**
* 查询所有
* @return
*/
public List<Student> getAll();

 

SQL映射文件，做如下设置

 

<mapper namespace="cn.happy.dao.IStudentDAO">

 

 

<select id="getAll" resultMap="studentMap" useCache="false">
    select * from student
</select>

</mapper>

测试类：

/**
 * 查询所有
 */
@Test
public void getAll() throws Exception{
    SqlSession session = MyBatisUtil.getSession();
    IStudentDAO mapper = session.getMapper(IStudentDAO.class);
    List<Student> all = mapper.getAll();
    for (Student item:all){
        System.out.println(item.getId()+   item.getName()+   item.getAge());
    }
    //提交事务
    session.commit();
    //关闭会话，释放资源
    session.close();
}

resultMap实现结果映射