1 实现添加操作

1. 编写接口方法:Mapper接口

2. 编写sql语句：sql映射文件

   <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

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)：设置为自动提交事务（关闭事务）

  @Testpublic void testAdd() throws Exception{int status = 1;String brandName = "波导";String companyName = "波导手机";String description = "手机中的战斗机";int ordered = 100;Brand brand = new Brand();brand.setStatus(status);brand.setBrandName(brandName);brand.setCompanyName(brandName);brand.setDescription(description);brand.setOrdered(ordered);// 加载mybatis的核心配置文件，获取SqlSessionFactoryString resource = "mybatis-config.xml";InputStream inputStream = Resources.getResourceAsStream(resource);SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);// 获取SqlSession对象，用它来执行sqlSqlSession sqlSession = sqlSessionFactory.openSession();// 获取UserMapper接口的代理对象BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);brandMapper.add(brand);sqlSession.commit();sqlSession.close();}

2 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的值

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

解决：

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