Mybatis学习总结（二）：增删改查

一、总体步骤

1、编写接口 2、实现接口 3、测试 （增删改需要提交事务）

二、增

//    增加一个用户
    int addUser(User user);

<insert id="addUser" parameterType="com.wc.pojo.User">
   insert into mybatis.user(id, name, pwd) values(#{
          
   id},#{
          
   name},#{
          
   pwd});
</insert>

@Test
    public void TestInsert(){
          
   
        SqlSession sqlSession = MybatisUtil.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        mapper.addUser(new User(5,"小蠢","2313"));

//        提交事务
        sqlSession.commit();
        sqlSession.close();
    }

三、删

//    删除用户
    int deleteUser(int id);

<delete id="deleteUser" parameterType="int" >
        delete from mybatis.user where id=#{
          
   id};
</delete>

@Test
    public void TestDelete(){
          
   
        SqlSession sqlSession = MybatisUtil.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.deleteUser(5);

        sqlSession.commit();
        sqlSession.close();
    }

四、改

//    修改用户
    int updateUser(User user);

<update id="updateUser" parameterType="com.wc.pojo.User">
        update mybatis.user set name = #{
          
   name},pwd=#{
          
   pwd} where id=#{
          
   id};
</update>

@Test
    public void TestUpdate(){
          
   
        SqlSession sqlSession = MybatisUtil.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.updateUser(new User(5,"小蠢","3266"));

        sqlSession.commit();

        sqlSession.close();
    }

五、查

//    根据id查询用户
    User getUserById(int id);

<select id="getUserById" resultType="com.wc.pojo.User" parameterType="int">
        select * from mybatis.user where id= #{
          
   id};
</select>

@Test
    public void TestGetUserById(){
          
   

        SqlSession sqlSession = MybatisUtil.getSqlSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = mapper.getUserById(1);
        System.out.print(user);
        sqlSession.close();
    }