案例-基于MVC和三层架构实现商品表的增删改查

package com.itheima.service; import com.itheima.mapper.BrandMapper; import com.itheima.pojo.Brand; import com.itheima.util.SqlSessionFactoryUtils; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import java.util.List; public class BrandService { SqlSessionFactory sqlSessionFactory =SqlSessionFactoryUtils.getSqlSessionFactory(); //查所有 public List<Brand> selectAll(){ //调用BrandMapper中的selectAll方法 //获取SqlSession SqlSession sqlSession = sqlSessionFactory.openSession(); //获取Mapper BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class); //调用方法 List<Brand> brands = brandMapper.selectAll(); sqlSession.close(); return brands; } //添加数据 public void add(Brand brand){ //调用BrandMapper中的selectAll方法 //获取SqlSession SqlSession sqlSession = sqlSessionFactory.openSession(); //获取Mapper BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class); //调用方法 brandMapper.add(brand); //提交事务 sqlSession.commit(); sqlSession.close(); } //回显 public Brand selectById(int id){ //调用BrandMapper中的selectById方法 //获取SqlSession SqlSession sqlSession = sqlSessionFactory.openSession(); //获取Mapper BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class); //调用方法 Brand brand = brandMapper.selectById(id); sqlSession.close(); return brand; } // 修改 public void update(Brand brand){ //调用BrandMapper中的selectById方法 //获取SqlSession SqlSession sqlSession = sqlSessionFactory.openSession(); //获取Mapper BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class); //调用方法 brandMapper.update(brand); //提交 sqlSession.commit(); sqlSession.close(); } public void deleteById(int id){ SqlSession sqlSession = sqlSessionFactory.openSession(); BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class); brandMapper.deleteById(id); sqlSession.commit(); sqlSession.close(); } }