MyBaits系列（二）MyBatis实现增删改查的两种方式

冷不防 2023-01-16 11:20 68阅读 0赞

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扩展：[MyBatis系列学习汇总][MyBatis]

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### 文章目录 ###

*   *   *   *  一、实体类实现增删改查
             *   *  1.1、增 > insert
                 *  1.2、删 > delete
                 *  1.3、改 > update
                 *  1.4、查 > select
             *  二、Map实现增删改查

#### 一、实体类实现增删改查 ####

*  前置条件跟上一篇的一样，这里不在重复，这里只讲实现方式！

##### 1.1、增 > insert #####

①抽象接口

Integer addUserInfo(User user);

②xml

*  这里要注意关键字的书写方式
 *  like要用`飘号`来包起来，防止跟关键字引起冲突！

<insert id="addUserInfo" parameterType="com.dbright.pojo.User">
            insert into user(name,age,`like`)values(#{name},#{age},#{like} )
        </insert>

③测试类

*  `session.commit();` 这个是提交事务！必须得写，不然语句不会生效！

@Test
        public void addUserInfo() { 
            SqlSession session = MybatisUtils.getSession();
            UserMapper mapper = session.getMapper(UserMapper.class);
    
            //造数据
            User user = new User();
            user.setName("面条");
            user.setAge(22);
            user.setLike("王者荣耀");
            Integer statusNum = mapper.addUserInfo(user);
            System.out.println(statusNum);
    
            session.commit();//提交事务
            session.close();
        }

④执行结果  
![在这里插入图片描述][2021042519262063.png]  
![在这里插入图片描述][20210425192642911.png]

##### 1.2、删 > delete #####

①抽象接口

Integer deleteUserInfo(int id);

②xml

<delete id="deleteUserInfo" parameterType="int">
            delete from user where id = #{id}
        </delete>

③测试类

*  删除也需要提交事务才会生效！

@Test
        public void deleteUserInfo() { 
            SqlSession session = MybatisUtils.getSession();
            UserMapper mapper = session.getMapper(UserMapper.class);
            Integer statusNum = mapper.deleteUserInfo(26);
            System.out.println(statusNum);
    
            session.commit();//提交事务
            session.close();
        }

④执行结果  
![在这里插入图片描述][2021042519290699.png]

##### 1.3、改 > update #####

①抽象接口

Integer updateUserInfo(User user);

②xml

<update id="updateUserInfo" parameterType="com.dbright.pojo.User">
            update user set name = #{name},age = #{age},`like` = #{like} where id = #{id}
        </update>

③测试类

@Test
        public void updateUserInfo() { 
            SqlSession session = MybatisUtils.getSession();
            UserMapper mapper = session.getMapper(UserMapper.class);
    
            //造数据
            User user = new User();
            user.setId(30);
            user.setName("丁大大");
            user.setAge(23);
            user.setLike("钓鱼");
            Integer statusNum = mapper.updateUserInfo(user);
            System.out.println(statusNum);
    
            session.commit();//提交事务
            session.close();
        }

④执行结果

*  原先：  
    ![在这里插入图片描述][20210425193234491.png]
 *  执行后：  
    ![在这里插入图片描述][20210425193252526.png]

##### 1.4、查 > select #####

①抽象接口

List<User> getUserInfo();
    
        User getUserInfoById(int id);
    
        User getUserInfoByIF(@Param("name") String name , @Param("age") Integer age);

②xml

<select id="getUserInfo" resultType="com.dbright.pojo.User">
            select * from user
        </select>
    
        <select id="getUserInfoById" resultType="com.dbright.pojo.User">
            select
                   *
            from
                 user
            where
                id = #{id}
        </select>
    
        <select id="getUserInfoByIF" resultType="com.dbright.pojo.User">
            select
                   *
            from
                 `user`
            where
                `name` = #{name}
            and
                age = #{age}
        </select>

③测试类

@Test
       public void selectUser() { 
           SqlSession session = MybatisUtils.getSession();
           UserMapper mapper = session.getMapper(UserMapper.class);
           List<User> users = mapper.getUserInfo();
    
           for (User map: users){ 
               System.out.println(map);
          }
           session.close();
      }
      @Test
      public void getUserInfoById() { 
          SqlSession session = MybatisUtils.getSession();
          UserMapper mapper = session.getMapper(UserMapper.class);
    
          User userInfo = mapper.getUserInfoById(30);
          System.out.println(userInfo);
    
          session.close();
      }
    
        @Test
        public void getUserInfoByIF() { 
            SqlSession session = MybatisUtils.getSession();
            UserMapper mapper = session.getMapper(UserMapper.class);
    
            User userInfo = mapper.getUserInfoByIF("丁大大",23);
            System.out.println(userInfo);
    
            session.close();
        }

④执行结果

*  数据如下：  
    ![在这里插入图片描述][20210425193454752.png]
 *  查询表里所有信息  
    ![在这里插入图片描述][202104251935308.png]
 *  待条件查询  
    ![在这里插入图片描述][20210425193559488.png]
 *  多条件查询  
    ![在这里插入图片描述][20210425193628349.png]

#### 二、Map实现增删改查 ####

*  这里不举太多例子了，因为mapper会自动将map中的值根据key对应起来
 *  十分方便，在实际工作中，使用Map查询居多
 *  前提是前后端联调使用的是`PostMan`或者`Yapi`等联调工具
 *  如果使用`swaager`联调，必须使用实体类来进行开发
 *  例子：  
    ①接口类

Integer addUserInfo(Map<String,Object> map);

②xml

<insert id="addUserInfo" parameterType="map">
            insert into user(name,age,`like`)values(#{name},#{age},#{like} )
        </insert>

③测试类

@Test
        public void addUserInfo() { 
            SqlSession session = MybatisUtils.getSession();
            UserMapper mapper = session.getMapper(UserMapper.class);
    
            //造数据
            Map<String,Object> map = new HashMap<>();
            map.put("name","面条");
            map.put("age","50");
            map.put("like","王者荣耀");
            Integer statusNum = mapper.addUserInfo(map);
            System.out.println(statusNum);
    
            session.commit();//提交事务
            session.close();
        }

④执行结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzgyOTQ0Mw_size_16_color_FFFFFF_t_70]

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[MyBatis]: https://blog.csdn.net/weixin_43829443/article/details/115354172?spm=1001.2014.3001.5502
[2021042519262063.png]: /images/20221022/e85e677bb150433eb44816ce5a5f5aa4.png
[20210425192642911.png]: /images/20221022/c8b01503b42741abb873962b655060e7.png
[2021042519290699.png]: /images/20221022/b630e40da26c459a9c958c0782360bf4.png
[20210425193234491.png]: /images/20221022/ceec48de37d84ca589e8f0b1a30d77fe.png
[20210425193252526.png]: /images/20221022/dec2f8939b1d416bb3c8694382af963a.png
[20210425193454752.png]: /images/20221022/9c2a201c14134e7084581c6c85c6f523.png
[202104251935308.png]: /images/20221022/bb474f5bb1fd43b4b9548f9c20c61ad3.png
[20210425193559488.png]: /images/20221022/e9844033308344e887e6e028927be63d.png
[20210425193628349.png]: /images/20221022/4ec47e45b21c44eabd745d036c47da85.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzgyOTQ0Mw_size_16_color_FFFFFF_t_70]: /images/20221022/6944bfc434e34c9da4c60d10a59b7555.png