[Mybatis]2.增删改

1.增

1.在接口中写int addUser(User user);
2.在xml中写：

    
        insert into mybatis1.user(id,name,password) values(#{id},#{name},#{password});
    

参数类型为实体类user，可以直接使用#{id},#{name},#{password}去实体类中取值
3.写测试方法

    @Test
    public void testInsert(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);;
        User user = new User(3,"李四","123456");
        System.out.println(user);
        mapper.addUser(user);
        sqlSession.commit();
        sqlSession.close();
    }

注意，增删改必须提交事务！ sqlSession.commit();

2.删

1.在接口中写int deleteUser(int id);
2.在xml中写：

    
        delete from user where id = #{id}
    

参数类型为实体类user，可以直接使用#{id},#{name},#{password}去实体类中取值
3.写测试方法

    @Test
    public void testDelete(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);;
        mapper.deleteUser(3);
        sqlSession.commit();
        sqlSession.close();
    }

3.改

1.在接口中写int updateUser(User user);
2.在xml中写：

    
        update mybatis1.user set name = #{name} where id = #{id}
    

参数类型为实体类user，可以直接使用#{id},#{name},#{password}去实体类中取值
3.写测试方法

    @Test
    public void testUpdate(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);;
        User user = new User(3,"王五","123456");
        System.out.println(user);
        mapper.updateUser(user);
        sqlSession.commit();
        sqlSession.close();
    }