Cookie模拟记住密码

记住密码登录成功后把用户名和密码存到cookie中，当第二次的时候用户名和密码会显示到登录框中

login.jsp页面

<%@page import="java.net.URLDecoder"%>
<%@page import="com.lanou3g.utils.CookieUtis"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录</title>
</head>
<body>
	<%
		String username = CookieUtis.getCookieValue("username", request);
		if(username != null) {
			username = URLDecoder.decode(username, "UTF-8");	
		} else {
			username = "";
		}
		
		pageContext.setAttribute("username", username);
		
		
		String password = CookieUtis.getCookieValue("password", request);
		if(password != null) {
			//解码用decode
			password = URLDecoder.decode(password, "UTF-8");	
		} else {
			password = "";
		}
		pageContext.setAttribute("password", password);
		
	%>
	<form action="login" method="post">
		<p>真实姓名：<input type="text" name="realname" /></p>
		<p>账号：<input type="text" name="username" value="${username }" /></p>
		<p>密码：<input type="password" name="password" value="${password }" /></p>
		<p>
			<input type="checkbox" name="rememberMe" />记住密码
			<input type="submit" value="登录" />
		</p>
	</form>
</body>
</html>

后台页面代码实现


import java.io.IOException;
import java.io.PrintWriter;
import java.net.URLEncoder;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.lanou3g.utils.CookieUtis;
@WebServlet("/login")
public class LoginServlet extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setCharacterEncoding("UTF-8");
		String realname = req.getParameter("realname");
		String username = req.getParameter("username");
		String password = req.getParameter("password");
		
		String rememberMe = req.getParameter("rememberMe");
		if(rememberMe != null && "on".equals(rememberMe)) {
			// 勾上了记住密码
			// 记住密码
			// {key:xx , val: xx}
			// 存储方式一：
			// {key: 'user-' + username, val: password}
			// 存储方式二：
			// {key: 'username', val: username}
			// {key: 'password', val: password}
			
			//编码用encode
			String encodeUsername = URLEncoder.encode(username, "UTF-8");
			String encodePassword = URLEncoder.encode(password, "UTF-8");
			Cookie userNameCookie = new Cookie("username", encodeUsername);
			userNameCookie.setMaxAge(60 * 60 * 24 * 7); // 设置过期时间为一周 
			
			Cookie passwordCookie = new Cookie("password", encodePassword);
			passwordCookie.setMaxAge(60 * 60 * 24 * 7); // 设置过期时间为一周
			
			resp.addCookie(userNameCookie);
			resp.addCookie(passwordCookie);
		}else {
			Cookie userCookie = CookieUtis.getCookie("username", req);
			Cookie pwdCookie = CookieUtis.getCookie("password", req);
			if(userCookie != null) {
				userCookie.setMaxAge(0);
				resp.addCookie(userCookie);
			}
			if(pwdCookie != null) {
				pwdCookie.setMaxAge(0);
				resp.addCookie(pwdCookie);
			}
		}
		resp.setContentType("text/html;charset=UTF-8");
		
		PrintWriter out = resp.getWriter();
		
		out.println("<h1>登录成功，"+realname+"欢迎您</h1>");
		
		out.println("<a href='login.jsp'>退出</a>");
		
	}
}

cookieUtils_126">cookieUtils中代码实现

package com.lanou3g.utils;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;

public class CookieUtis {

	/**
	 * 按照cookie的key获取对应的value
	 * @param key
	 * @param req
	 * @return
	 */
	public static String getCookieValue(String key, HttpServletRequest req) {
		Cookie cookie = getCookie(key, req);
		return cookie != null ? cookie.getValue() : null;
	}
	
	/**
	 * 按照cookie的key获取对应的cookie对象
	 * @param key
	 * @param req
	 * turn
	 */
	public static Cookie getCookie(String key, HttpServletRequest req) {
		Cookie[] cookies = req.getCookies();
		if (cookies == null) {
			return null;
		}
		for (Cookie cookie : cookies) {
			if (cookie.getName().equals(key)) {
				return cookie;
			}
		}
		return null;
	}
}