信息的保存与获取
例如简单的网上购物，将购买者的姓名、商品名保存在session对象中，实现一个web目录下的页面对session对象中信息的共享。要求创建3个页面，第一个页面输入用户的姓名，第二个页面输入购买商品的名称，第三个页面实现结账处理！
name.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>
<body>
<form action="commodity.jsp" method="post">
<p>姓名：<input name="username" type="text"></p>
<input type="submit" value="进入">
</form>
</body>
</html>
commodity.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>
<body>
<%
String username = request.getParameter("username");
session.setAttribute("username", username);
%>
<p>apple：3元</p>
<p>orange：2元</p>
<p>banana：4元</p>
<form action="account.jsp" method="post" name="form">
请输入你想购买的产品名称：<br><br><input type="text" name="commodityName"><br><br>
<input type="submit" value="提交">
</form>
</body>
</html>
account.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>
<body>
<%
String commodityname = request.getParameter("commodityName");
session.setAttribute("commodityname",commodityname);
%>
<%
Object name= session.getAttribute("username");
Object commodity = (String)session.getAttribute("commodityname");
%>
<%! int count=0; %>
<%
if(name != null){
out.print("进行结账:<br><br>");
out.print("姓名："+name.toString()+"<br>");
out.print("<br>");
if(commodity != null){
if(commodity.equals("apple")){
out.print("您所购买的是"+commodity+";<br><br>您所需要支付的金额为3元");
}
if(commodity.equals("orange")){
out.print("您所购买的是"+commodity+";<br><br>您所需要支付的金额为2元");
}
if(commodity.equals("banana")){
out.print("您所购买的是"+commodity+";<br><br>您所需要支付的金额为4元");
}
}
else{
out.print("未购买商品，应支付金额为：0元");
}%>
<a href="https://auth.alipay.com/login/index.htm?goto=https%3A%2F%2Fwww.alipay.com%2F" color="blue"><br><br>支付宝支付</a>
<%}
%>
</body>
</html>
实现结果：
