JSP的Cookie在登录中的使用方法

cookie是浏览器访问某些网站后存储在客户端的一组数据，用于使网站跟踪用户，实现用户自定义功能，那么JSP的Cookie在登录中的使用方法大家了解多少呢？别着急，中国E盟技术频道小编为你细细道来。

JSP的Cookie在登录中的使用

一功能需求

实现记忆用户名和密码功能。

二代码

1、login.jsp

<%@ 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%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  
  <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" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
    -->
 </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>

2、dologin.jsp

<%@ 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%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  
  <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" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
    -->
 
 </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" rel="external nofollow" target="_blank">查看用户信息</a>
  
 </body>
 
</html>

3、users.jsp

<%@ 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%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  
  <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" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
    -->
 
 </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>

三测试