Jsp+Servlet实现购物车功能

 
 商品:
 
 洗衣粉
 香皂
 食用油
 
 
数量:
 
 
 
 
 
 
 查看购物车

package com.lc.shoppingCar;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class AddItemServlet extends HttpServlet 
{ 
 protected void doGet(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,java.io.IOException
 {
 ServletContext application=getServletContext() ;
 ServletConfig cOnfig=getServletConfig() ;
 response.setContentType("text/html;charset=gb2312");
 PrintWriter out=response.getWriter(); 
 HttpSession session =request.getSession();
 request.setCharacterEncoding("gb2312");
 
 //读取表单传入的商品ID及数量
 String id=request.getParameter("itemID"); 
 String num=request.getParameter("quantity");
 if(id!=null && num.length()!=0)
 { //从Sessionn中读取购物车
 HashMap shoppingCar=(HashMap)session.getAttribute("shoppingCar");
 if(shoppingCar==null)
 shoppingCar=new HashMap();
 //将商品加入到购物车中
 String Onum=(String)shoppingCar.get(id);
 if(Onum==null)
  shoppingCar.put(id,num);
 else
 {
 int n1=Integer.parseInt(num);
 int n2=Integer.parseInt(onum);
 String result=String.valueOf(n1+n2);
 shoppingCar.put(id,result);
 } 
  //将购物车写回session中保存
 session.setAttribute("shoppingCar",shoppingCar); 
 }
 else //假设传入的商品ID号为空或数量为空。显示提示信息
 System.out.print("商品ID号为空会或数量为空！");
 //返回商品列表页
 response.sendRedirect("/servletProject/exam403.jsp"); 
 } 
 
protected void doPost(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,java.io.IOException
 {
 doGet(request,response);
 }
}

package com.lc.shoppingCar;


import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class ListItemServlet extends HttpServlet 
{ 
 protected void doGet(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,java.io.IOException
 {
 ServletContext application=getServletContext() ;
 ServletConfig cOnfig=getServletConfig() ;
 response.setContentType("text/html;charset=gb2312");
 PrintWriter out=response.getWriter(); 
 HttpSession session =request.getSession();
 request.setCharacterEncoding("gb2312");
 
 //从session中获取购物车
 HashMap shoppingCar=(HashMap)session.getAttribute("shoppingCar");
 //显示购物车中的内容
 if(shoppingCar!=null)
 {
 Set show=shoppingCar.entrySet();
 Iterator it=show.iterator();
 while(it.hasNext())
 {
  out.print(it.next()+"
");
 }
 }
 else
 out.print("购物车为空。"); 
 } 
 
protected void doPost(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,java.io.IOException
 {
 doGet(request,response);
 }
}