文件说明：
products.jsp ------ 购物车列表
buyServlet.java ------- 购物servlet
cart.jsp ----- 查看购物车
ClearServlet ---- 清空购物车
products.jsp
<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>购物车</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<h3>商品出售列表</h3>
画家<a href="/Day0707/buy?id=1">购买</a><br/>
基地<a href="/Day0707/buy?id=2">购买</a><br/>
77169<a href="/Day0707/buy?id=3">购买</a><br/>
百度<a href="/Day0707/buy?id=4">购买</a><br/>
优酷<a href="/Day0707/buy?id=5">购买</a><br/>
<hr/>
<br/><a href='/Day0707/cart.jsp'>查看购物车</a>
<br/><a href='/Day0707/clear'>清空购物车</a>
</body>
</html>
buyServlet.java
package com.gyarmy.session;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class BuyServlet extends HttpServlet {
// 获取购买的商品信息
/*
*
*
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String id = request.getParameter("id");
String[] bookNames = { "画家", "基地", "77169", "百度", "优酷" };
String bookName = bookNames[Integer.parseInt(id) - 1];
Map<String, Integer> cart = (Map<String, Integer>) request.getSession()
.getAttribute("cart");
if(cart == null){
cart = new HashMap<String, Integer>();
}
if(cart.containsKey(bookName)){
//购买过
Integer count = cart.get(bookName);
cart.put(bookName, count+1);
}else{
//新购买
cart.put(bookName, 1);
}
//放入session中
request.getSession().setAttribute("cart", cart);
response.setContentType("text/html;charset=utf-8");
response.getWriter().print("添加购物车成功!...<a href='/Day0707/products.jsp'>继续购买</a>");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
3 cart.jsp
<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>购物车展示</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%
//拿到购物车
Map<String,Integer> cart =(Map<String,Integer>) request.getSession().getAttribute("cart");
if(cart == null)
{
out.print("您还没有购买任何商品!..<a href='/Day0707/products.jsp'>继续购买</a>");
}else{
//遍历购物车，取出商品
out.print("购物商品如下:<br/>");
for (String key : cart.keySet()) {
out.print("书本:"+ key + " 数量: " + cart.get(key)+"<br/>");
}
out.print("<br/><a href='/Day0707/products.jsp'>继续购买</a>");
}
%>
</body>
</html>
4 \clearServlet
package com.gyarmy.session;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ClearCartServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//清空session
//request.getSession().invalidate();
request.getSession().removeAttribute("cart");
response.setContentType("text/html;charset=utf-8");
response.getWriter().print("清空购物车成功!<br/>");
response.getWriter().print("<a href='/Day0707/products.jsp'>继续购买</a>");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}