MyBatis的添加和修改命令

2. 添加

   1.编写接口方法：Mapper接口

   在BrandMapper类添加方法

   /**
    * 添加
    */
   void add(Brand brand);

    

    

   参数：除了id之外的所有数据

   结果：void

   2.编写SQL语句：SQL映射文件

   在BrandMapper.xml类添加

   <insert id="add">
   ​
       insert into tb_brand (brand_name,company_name,ordered,description,status)
       values (#{brandName},#{companyName},#{ordered},#{description},#{status});
   ​
   </insert>

    

   3.执行方法，测试

   Add方法测试

   @Test
   public void testAdd() throws IOException {
   ​
       //接收参数
       int status = 1;
       String companyName = "波导手机";
       String brandName = "波导";
       String description = "手机中的战斗机";
       int ordered = 100;
   ​
   ​
       //封装对象
       Brand brand = new Brand();
       brand.setStatus(status);
       brand.setCompanyName(companyName);
       brand.setBrandName(brandName);
       brand.setDescription(description);
       brand.setOrdered(ordered);
   ​
   ​
   ​
       //1.获取SqlSessionFactory
       String resource = "mybatis-config.xml";
       InputStream inputStream = Resources.getResourceAsStream(resource);
       SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
   ​
       //2.获取SqlSession对象
       //SqlSession sqlSession = sqlSessionFactory.openSession();
       SqlSession sqlSession = sqlSessionFactory.openSession(true);
   ​
       //3.获取Mapper接口的代理对象
       BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);
   ​
       //4.执行方法
   ​
       brandMapper.add(brand);
   ​
       //提交事务
       sqlSession.commit();
   ​
       //5.释放资源
       sqlSession.close();
   ​
   }

    

   MyBatis事务：

   openSession():默认开启事务，进行增删改操作后需要使用sqlSession.commit();手动提交事务

   openSession(true):可以设置为自动提交事务（关闭事务）

   添加-主键返回

   在数据添加成功后，需要获取插入数据库数据的主键

   返回添加数据的主键

   映射文件

   <insert id="add" useGeneratedKeys="true" keyProperty="id">

    

   比如：添加订单和订单项

   1.添加订单

   2.添加订单项，订单项中需要设置所属订单的id

   测试类

   @Test
   public void testAdd2() throws IOException {
   ​
       //接收参数
       int status = 1;
       String companyName = "波导手机";
       String brandName = "波导";
       String description = "手机中的战斗机";
       int ordered = 100;
   ​
   ​
       //封装对象
       Brand brand = new Brand();
       brand.setStatus(status);
       brand.setCompanyName(companyName);
       brand.setBrandName(brandName);
       brand.setDescription(description);
       brand.setOrdered(ordered);
   ​
   ​
   ​
       //1.获取SqlSessionFactory
       String resource = "mybatis-config.xml";
       InputStream inputStream = Resources.getResourceAsStream(resource);
       SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
   ​
       //2.获取SqlSession对象
       //SqlSession sqlSession = sqlSessionFactory.openSession();
       SqlSession sqlSession = sqlSessionFactory.openSession(true);
   ​
       //3.获取Mapper接口的代理对象
       BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);
   ​
       //4.执行方法
   ​
       brandMapper.add(brand);
       Integer id = brand.getId();
       System.out.println(id);
   ​
       //提交事务
       sqlSession.commit();
   ​
       //5.释放资源
       sqlSession.close();
   ​
   }

    

3. 修改

   1. 修改全部自动

      1.编写接口方法Mapper接口

      参数：所有数据

      结果：void

      BrandMapper类

      /**
       * 修改
       */
      int update(Brand brand);

       

      2.编写SQL语句：SQL映射文件

      BrandMapper.xml文件

      <update id="update">
          update tb_brand
          set
              brand_name = #{brandName},
              company_name = #{companyName},
              ordered = #{ordered},
              description = #{description},
              status = #{status}
          where id = #{id};
      ​
      </update>

       

      3.执行方法测试

      测试类

      @Test
      public void testUpdate() throws IOException {
      ​
          //接收参数
          int status = 1;
          String companyName = "波导手机";
          String brandName = "波导";
          String description = "波导手机,手机中的战斗机";
          int ordered = 200;
          int id = 5;
      ​
      ​
          //封装对象
          Brand brand = new Brand();
          brand.setStatus(status);
          brand.setCompanyName(companyName);
          brand.setBrandName(brandName);
          brand.setDescription(description);
          brand.setOrdered(ordered);
          brand.setId(id);
      ​
      ​
      ​
          //1.获取SqlSessionFactory
          String resource = "mybatis-config.xml";
          InputStream inputStream = Resources.getResourceAsStream(resource);
          SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
      ​
          //2.获取SqlSession对象
          //SqlSession sqlSession = sqlSessionFactory.openSession();
          SqlSession sqlSession = sqlSessionFactory.openSession(true);
      ​
          //3.获取Mapper接口的代理对象
          BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);
      ​
          //4.执行方法
          int count = brandMapper.update(brand);
          System.out.println(count);
      ​
          //提交事务
          sqlSession.commit();
      ​
          //5.释放资源
          sqlSession.close();
      ​
      }

       

   2. 修改动态字段

      1.编写接口方法：Mapper接口

      参数：部分数据，封装到对象中

      结果：void

      跟BrandMapper类一样没变化。

      2.编写SQL语句：SQL映射文件

      改变BrandMapper.xml的SQL语句

      <update id="update">
          update tb_brand
          <set>
          <if test="brandName != null and brandName != ''">
              brand_name = #{brandName},
          </if>
      ​
          <if test="companyName != null and companyName != '' ">
              company_name = #{companyName},
          </if>
      ​
          <if test="ordered != null">
              ordered = #{ordered},
          </if>
      ​
          <if test="description != null and description != ''">
              description = #{description},
          </if>
      ​
          <if test="status != null">
              status = #{status}
          </if>
          </set>
      ​
          where id = #{id};
      ​
      </update>

       

      3.执行方法，测试

      测试类

       @Test
          public void testUpdate() throws IOException {
      ​
              //接收参数
              int status = 0;
              String companyName = "波导手机";
              String brandName = "波导";
              String description = "波导手机,手机中的战斗机";
              int ordered = 200;
              int id = 6;
      ​
      ​
              //封装对象
              Brand brand = new Brand();
              brand.setStatus(status);
      //        brand.setCompanyName(companyName);
      //        brand.setBrandName(brandName);
      //        brand.setDescription(description);
      //        brand.setOrdered(ordered);
              brand.setId(id);
      ​
      ​
      ​
              //1.获取SqlSessionFactory
              String resource = "mybatis-config.xml";
              InputStream inputStream = Resources.getResourceAsStream(resource);
              SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
      ​
              //2.获取SqlSession对象
              //SqlSession sqlSession = sqlSessionFactory.openSession();
              SqlSession sqlSession = sqlSessionFactory.openSession(true);
      ​
              //3.获取Mapper接口的代理对象
              BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);
      ​
              //4.执行方法
              int count = brandMapper.update(brand);
              System.out.println(count);
      ​
              //提交事务
              sqlSession.commit();
      ​
              //5.释放资源
              sqlSession.close();
      ​
          }