68 cookie在登录中的作用

定义一个login.jsp页面

<%@ page language="java" import="java.util.*,java.net.*" contentType="text/html; charset=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><h1>用户登录</h1><hr><% request.setCharacterEncoding("utf-8");String username="";String password = "";Cookie[] cookies = request.getCookies();if(cookies!=null&&cookies.length>0){for(Cookie c:cookies){if(c.getName().equals("username")){username =  URLDecoder.decode(c.getValue(),"utf-8");}if(c.getName().equals("password")){password =  URLDecoder.decode(c.getValue(),"utf-8");}}}%><form name="loginForm" action="dologin.jsp" method="post"><table><tr><td>用户名：</td><td><input type="text" name="username" value="<%=username %>"/></td></tr><tr><td>密码：</td><td><input type="password" name="password" value="<%=password %>" /></td></tr><tr><td colspan="2"><input type="checkbox" name="isUseCookie" checked="checked"/>十天内记住我的登录状态</td></tr><tr><td colspan="2" align="center"><input type="submit" value="登录"/><input type="reset" value="取消"/></td></tr></table></form></body>
</html>

定义一个dologin的jsp页面

<%@ page language="java" import="java.util.*,java.net.*" contentType="text/html; charset=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 'dologin.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><h1>登录成功</h1><hr><br><br><br><% request.setCharacterEncoding("utf-8");//首先判断用户是否选择了记住登录状态String[] isUseCookies = request.getParameterValues("isUseCookie");if(isUseCookies!=null&&isUseCookies.length>0){//把用户名和密码保存在Cookie对象里面String username = URLEncoder.encode(request.getParameter("username"),"utf-8");//使用URLEncoder解决无法在Cookie当中保存中文字符串问题String password = URLEncoder.encode(request.getParameter("password"),"utf-8");Cookie usernameCookie = new Cookie("username",username);Cookie passwordCookie = new Cookie("password",password);usernameCookie.setMaxAge(864000);passwordCookie.setMaxAge(864000);//设置最大生存期限为10天response.addCookie(usernameCookie);response.addCookie(passwordCookie);}else{Cookie[] cookies = request.getCookies();if(cookies!=null&&cookies.length>0){for(Cookie c:cookies){if(c.getName().equals("username")||c.getName().equals("password")){c.setMaxAge(0); //设置Cookie失效response.addCookie(c); //重新保存。}}}}%><a href="users.jsp" target="_blank">查看用户信息</a></body>
</html>

定义一个user的jsp页面

<%@ page language="java" import="java.util.*,java.net.*" contentType="text/html; charset=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 'users.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><h1>用户信息</h1><hr><% request.setCharacterEncoding("utf-8");String username="";String password = "";Cookie[] cookies = request.getCookies();if(cookies!=null&&cookies.length>0){for(Cookie c:cookies){if(c.getName().equals("username")){username = URLDecoder.decode(c.getValue(),"utf-8");}if(c.getName().equals("password")){password = URLDecoder.decode(c.getValue(),"utf-8");}}}%><BR><BR><BR>用户名：<%=username %><br>密码：<%=password %><br></body>
</html>

运行结果