Jsp+Servlet实现购物车功能

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本文实例为大家分享了Servlet实现购物车功能的具体代码，供大家参考，具体内容如下

(1)用servlet实现简单的购物车系统，项目结构例如以下：（新建web Project项目仅仅须要AddItemServlet ， ListItemServlet。exam403.jsp三个文件就可以。其它的不用管）

（2）exam403.jsp代码例如以下：

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
</head>

<body>
<form id="form1" name="form1" method="post" action="/servletProject/addItem">
 <label></label>
 商品:
 <select name="itemID" id="itemID">
 <option value="洗衣粉">洗衣粉</option>
 <option value="香皂">香皂</option>
 <option value="食用油">食用油</option>
 </select>
 <p>数量:
 <label>
 <input name="quantity" type="text" id="quantity" value="1" />
 </label>
 <label>
 <input type="submit" name="Submit" value="提交" />
 </label>
 <a href="/servletProject/listItem">查看购物车</a></p>
</form>
</body>
</html>

（3）AddItemServlet代码例如以下：

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);
 }
}

（4）ListItemServlet代码例如以下：

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()+"<br>");
 }
 }
 else
 out.print("购物车为空。"); 
 } 
 
protected void doPost(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,java.io.IOException
 {
 doGet(request,response);
 }
}

（5）实现效果例如以下：

訪问：http://localhost:8080/servletProject/exam403.jsp 学则商品提交