Cookie是小段的文本信息，在网络服务器上生成，并发送给浏览器，通过使用cookie可以标识用户身份，记录用户名和密码，跟踪重复等。
首先创建index.jsp：
<%@page import="java.net.URLDecoder"%> <%@page import="javax.activation.URLDataSource"%> <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <% 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 'index.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"> --> </head> <body> <% Cookie[] cookies=request.getCookies(); //从request中获得cookie对象的集合 String user=""; String date=""; if(cookies !=null){ //遍历cookie对象集合 for(int i=0;i<cookies.length;i++){ if(cookies[i].getName().equals("cdp")){ user=URLDecoder.decode(cookies[i].getValue().split("#")[0]); //获取用户名 date=cookies[i].getValue().split("#")[1]; //获取注册时间 } } } if("".equals(user)&&"".equals(date)){ //如果没有注册 %> <p> 游客您好，欢迎初次光临！ </p> <form action="MyJsp.jsp method="post"></form> 请输入姓名:<input name="user" type="text" value=""><br> <input type="submit" value="确定"> <% }else{ //已注册 %> 欢迎<b><%=user %>再次光临<br> 你注册的时间是:<%=date %> <% } %> </body> </html>
再创建MyJsp.jsp，用于向cookie中写入对象注册信息：
<%@page import="java.net.URLEncoder"%> <%@page import="java.net.URLDecoder"%> <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <% 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 'MyJsp.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"> --> </head> <body> <% request.setCharacterEncoding("GB18030"); //设置请求的编译为GB18030 String user=URLEncoder.encode(request.getParameter("user"),"utf-8"); //获取用户名 Cookie cookie=new Cookie("cdp",user+"#"+new java.util.Date().toLocaleString()); //创建并实例化Cookie对象 cookie.setMaxAge(60*60*24*30); //设置Cookie有效时间为30天 response.addCookie(cookie); //保存Cookie %> <script type="text/javascript">window.location.href="index.jsp"</script> </body> </html>