Cookie实现自动登录

 

登录页面:

 

<%@ 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 'login.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>
  <%
  request.setCharacterEncoding("UTF-8");
  Cookie [] cookies=request.getCookies();
  if(cookies!=null&&cookies.length>0){
	  for(int i=0;i<cookies.length;i++){
		  Cookie cookie=cookies[i];
		  if("name".equals(cookie.getName())){
			  session.setAttribute("name",cookie.getValue());
			  response.sendRedirect(response.encodeRedirectURL("index.jsp"));
		  }
	  }
  }
  %>
  <body style="text-align: center;">
    <form action="TestServlet" method="post">
	    用户名: <input type="text" name="name"/><br/>
	    密&nbsp;&nbsp;&nbsp;码:<input type="password" name="password"/><br/>
	    <input type="submit" name="登录"/>
    </form>
  </body>
</html>

 

 登录成功页面:

 

<%@ 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>
    欢迎你,<%=session.getAttribute("name") %>
  </body>
</html>

 

Servlet:

 

package com.TestCookie.biz;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class TestServlet extends HttpServlet {

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doPost(request, response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		response.setCharacterEncoding("UTF-8");
		HttpSession session=request.getSession();
		String name=request.getParameter("name");
		String password=request.getParameter("password");
		if ("Camey".equals(name)&&"123456".equals(password)) {
			Cookie cookie=new Cookie("name", name);
			cookie.setMaxAge(10000);
			response.addCookie(cookie);
			session.setAttribute("name", name);
			response.sendRedirect(response.encodeRedirectURL("index.jsp"));
		}
		out.flush();
		out.close();
	}

}

 注销登录

Cookie cookies[]=request.getCookies();
		if (cookies!=null) {
			for (int i = 0; i < cookies.length; i++) {
				if (cookies[i].getName().equals("gzqhName")) {
					cookies[i].setMaxAge(0);
					response.addCookie(cookies[i]);
				}
			}
		}

 通过改变cookie的生效时间从而达到销毁的目的

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