查select

1.编写接口

 2.编写对应的mapper中的sql语句

 3.测试

注意

maven项目的clean与package

Insert插入

    //insert一个用户
    int addUser(User user);

    </select>
    <!--对象的属性可以直接取出来-->
    <insert id="addUser" parameterType="com.cm.pojo.User">
        insert into mybatis.user (id, name, pwd) values (#{id},#{name},#{pwd});
    </insert>

    @Test
    public void addUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
       int res=mapper.addUser( new User(6,"ll","123456"));
        if(res>0){
            System.out.println("插入成功！");
        }
        //提交事务
        sqlSession.commit();
        sqlSession.close();
    }

修改用户

//修改用户
    int updateUser(User user);

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

   @Test
    public void updateUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        mapper.updateUser(new User(4,"jj","123456"));
        //提交事务
        sqlSession.commit();
        sqlSession.close();
    }

Delete删除

 //删除一个用户
    int deleteUser(int id);

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

    @Test
    public  void deleteUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        mapper.deleteUser(4);
        sqlSession.commit();
        sqlSession.close();
    }