本人写一个简单的商品浏览且具备记录商品浏览历史的功能的页面。记录商品浏览历史是用cookie实现的。但是每次用request.getCookies()获取我之前保存的cookie时都是获取不了。不是为何，请看代码。
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8" %>
<%@ page import="entity.Items"%>
<%@ page import="dao.ItemsDAO"%>
<%
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>My JSP 'details.jsp' starting page</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">
-->
<style type="text/css">
div{
float:left;
margin-left: 30px;
margin-right:30px;
margin-top: 5px;
margin-bottom: 5px;
}
div dd{
margin:0px;
font-size:10pt;
}
div dd.dd_name
{
color:blue;
}
div dd.dd_city
{
color:#000;
}
</style>
</head>
<body>
<h1>商品详情</h1>
<hr>
<center>
<table width="750" height="60" cellpadding="0" cellspacing="0" border="0">
<tr>
<!-- 商品详情 -->
<%
ItemsDAO itemsDAO = new ItemsDAO();
Items item = itemsDAO.getItemsById(Integer.valueOf(request.getParameter("id")) - 1);
if(item != null){
%>
<td width="70%" valign="top">
<table>
<tr>
<td rowspan="4"><img src="images/<%= item.getPicture() %>" width="200" height="160"/></td>
</tr>
<tr>
<!-- 商品名称 -->
<td><B><%= item.getName() %></B></td>
</tr>
<tr>
<td>产地：<%= item.getCity() %></td>
</tr>
<tr>
<td>价格：<%= item.getPrice() %>￥</td>
</tr>
</table>
</td>
<%
}
%>
<!-- 获取并更新cookies -->
<%
String list = "";
Cookie[] cookies = request.getCookies();
if(cookies != null && cookies.length > 0){
for(Cookie cookie: cookies){
if(cookie.getName().equals("HistoryItemList")){
list = cookie.getValue();
break;
}
}
}
System.out.println("前:" + list);
list += request.getParameter("id") + ";;";
System.out.println("后:" + list);
Cookie cookie = new Cookie("HistoryItemList", list);
response.addCookie(cookie);
%>
<!-- 浏览过的商品 -->
<td width="30%" bgcolor="#EEE" align="center">
<br>
<b>您浏览过的商品</b><br>
<!-- 循环开始 -->
<%
ArrayList<Items> historyItems = itemsDAO.getViewList(list);
if(historyItems!= null && historyItems.size() > 0){
for(Items items: historyItems){
%>
<div>
<dl>
<dt>
<a href="details.jsp?id=<%= items.getId() %>"><img src="images/<%= items.getPicture() %>" width="120" height="90" border="1"/></a>
</dt>
<dd class="dd_name"><%= items.getName() %></dd>
<dd class="dd_city">产地:<%= items.getCity() %> 价格:<%= items.getPrice() %>￥ </dd>
</dl>
</div>
<%
}
}
%>
<!-- 循环结束 -->
</td>
</tr>
</table>
</center>
</body>
</html>
