• servlet方式通过Cookie记住登录时的用户名和密码

    转自：http://www.cnblogs.com/thrilling/p/4924077.html

    1.建立web工程

    2.创建存放servlet的包

    3右键包，新建servlet，路径将前面的servlet去掉，只需要doPost和doGet方法

    编写servlet

    CookieServlet.java代码如下：

     1 package test1029;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.http.Cookie;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 
12 public class CookieServlet extends HttpServlet {
13 
14     public void doGet(HttpServletRequest request, HttpServletResponse response)
15             throws ServletException, IOException {
16         this.doPost(request, response);
17     }
18 
19     public void doPost(HttpServletRequest request, HttpServletResponse response)
20             throws ServletException, IOException {
21         response.setContentType("text/html");
22         
23         String uname=request.getParameter("uname");
24         String password=request.getParameter("password");
25         String ck=request.getParameter("ck");
26         
27         //被选中的状态是on 没有被选中的状态下是null
28         if("on".equals(ck)){
29         //构造Cookie对象
30         //添加到Cookie中
31         Cookie c=new Cookie("users", uname+"-"+password);
32         
33         //设置过期时间
34         c.setMaxAge(600);
35         
36         //存储
37         response.addCookie(c);
38     }
39     }
40 }

    配置文件web.xml

     1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
 3   <display-name>test1029</display-name>
 4   <servlet>
 5     <description>This is the description of my J2EE component</description>
 6     <display-name>This is the display name of my J2EE component</display-name>
 7     <servlet-name>CookieServlet</servlet-name>
 8     <servlet-class>test1029.CookieServlet</servlet-class>
 9   </servlet>
10 
11   <servlet-mapping>
12     <servlet-name>CookieServlet</servlet-name>
13     <url-pattern>/CookieServlet</url-pattern>
14   </servlet-mapping>
15   <welcome-file-list>
16     <welcome-file>index.html</welcome-file>
17     <welcome-file>index.htm</welcome-file>
18     <welcome-file>index.jsp</welcome-file>
19     <welcome-file>default.html</welcome-file>
20     <welcome-file>default.htm</welcome-file>
21     <welcome-file>default.jsp</welcome-file>
22   </welcome-file-list>
23 </web-app>

    index.jsp代码：

     1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 2 <%
 3 String path = request.getContextPath();
 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 5 %>
 6 
 7 <%
 8 
 9 //el表达式
10 String names="";
11 String pwd="";
12 //取出Cookie
13 Cookie [] c=request.getCookies();
14 for(int i=0;i<c.length;i++){
15     if(c[i].getName().equals("users")){
16         //存着数据（用户名+密码）
17         names=c[i].getValue().split("-")[0];
18         pwd=c[i].getValue().split("-")[1];
19         
20         //再一次的存起来（备用）
21         request.setAttribute("xingming",names);
22         request.setAttribute("mima", pwd);
23     }
24 }
25 
26  %>
27 
28 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
29 <html>
30   <head>
31     <base href="<%=basePath%>">
32     
33     <title>My JSP 'index.jsp' starting page</title>
34     <meta http-equiv="pragma" content="no-cache">
35     <meta http-equiv="cache-control" content="no-cache">
36     <meta http-equiv="expires" content="0">    
37     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
38     <meta http-equiv="description" content="This is my page">
39     <!--
40     <link rel="stylesheet" type="text/css" href="styles.css">
41     -->
42   </head>
43   
44   <body>
45     <form action="CookieServlet" method="post">
46         用户名:<input type="text" name="uname" id="uname" value="${xingming}"/><br>
47         密码:<input type="password" name="password" id="password" value="${mima }"/><br>
48         <input type="checkbox" name="ck">记住用户名和密码<br>
49         <input type="submit" value="登录">
50     </form>
51   </body>
52 </html>

    效果图：

    1、项目运行之后，先进入登录界面，填写用户名和密码，效果如下图

    2.登录后：

    3.重新访问登录页面，效果如下：

    http://images2015.cnblogs.com/blog/804095/201510/804095-20151030180333482-129830263.png

    <?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>test1029</display-name>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>CookieServlet</servlet-name>
    <servlet-class>test1029.CookieServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>CookieServlet</servlet-name>
    <url-pattern>/CookieServlet</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
</web-app>
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  • 原文地址：https://www.cnblogs.com/sharpest/p/5948457.html
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