购物车系统

				package com.estore.dao.impl;
				
				import java.util.*;
				
				import org.hibernate.*;
				
				import com.estore.dao.ShoppingCartDao;
				import com.estore.entity.*;
				import com.estore.util.*;
				
				public class ShoppingCartImpl implements ShoppingCartDao{
				
					public Product findProductById(Integer id){
						Session s = null;
						Transaction tran = null;
						Product product=new Product();
						try{
							s = HibernateUtil.getSession();
							tran =s.beginTransaction();
							String hql="from  Product where id=?";
							product=(Product)s.createQuery(hql).setInteger(0, id).uniqueResult();
							tran.commit();
						}catch(Exception e){
							product=null;
							tran.rollback();
							throw new RuntimeException(e.getMessage());
						}finally {
							 HibernateUtil.releaseSession(s);
						}
						return product;
					}
					
					
					public List listProducts() {
						List pros = new ArrayList();
						Session s = null;
						Transaction tran = null;
						try {
							s = HibernateUtil.getSession();
							tran = s.beginTransaction();
							String hql = "from Product p";
							Query q = s.createQuery(hql);
							pros =(List) q.list();
							tran.commit();
						} catch (Exception e) {
							e.printStackTrace();
							if (tran != null)
								tran.rollback();
						 }finally {
							 HibernateUtil.releaseSession(s);
						}
						return pros;
					}
				
				
					
					public Order findOrderByOrderId(Integer id){
						Session s = null;
						Transaction tran =null;
						Order order=new Order();
						try{
							s = HibernateUtil.getSession();
							tran =s.beginTransaction();
							String hql="from Order where id=?";
							order=(Order)s.createQuery(hql).setInteger(0,id).uniqueResult();
							tran.commit();
							return order;
						}catch(Exception e){
							tran.rollback();
							throw new RuntimeException(e.getMessage());
						}finally {
							 HibernateUtil.releaseSession(s);
						}
						
					}
					public User findUserByUserId(Integer id){
						Session s = null;
						Transaction tran = null;
						User user=new User();
						try{
							s = HibernateUtil.getSession();
							tran = s.beginTransaction();
							String hql="from User where id=?";
							user=(User)s.createQuery(hql).setInteger(0,id).uniqueResult();
							tran.commit();
							return user;
						}catch(Exception e){
							tran.rollback();
							throw new RuntimeException(e.getMessage());
						}finally {
							 HibernateUtil.releaseSession(s);
						}
						
					}
					
					
					public int generateOrder(Order order) {
						Session s = null;
						Transaction tran=null;
						try{
							s = HibernateUtil.getSession();
							tran=s.beginTransaction();
							s.save(order);
							tran.commit();
							return order.getOid(); 
							
						}catch(Exception e){
							tran.rollback();
							e.printStackTrace();
							throw new  RuntimeException(e.getMessage());
						}finally {
							 HibernateUtil.releaseSession(s);
						}
						
					}
				
				
				
				}