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jsp實(shí)現(xiàn)用戶自動(dòng)登錄功能

更新時(shí)間：2021年06月28日 15:27:54 作者：loving-cat

這篇文章主要為大家詳細(xì)介紹了jsp實(shí)現(xiàn)用戶自動(dòng)登錄功能，文中示例代碼介紹的非常詳細(xì)，具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

理解并掌握Cookie的作用以及利用cookie實(shí)現(xiàn)用戶的自動(dòng)登錄功能，實(shí)現(xiàn)下圖效果

當(dāng)服務(wù)器判斷出該用戶是首次登錄的時(shí)候，會(huì)自動(dòng)跳轉(zhuǎn)到登錄界面等待用戶登錄，并填入相關(guān)信息。通過設(shè)置Cookie的有效期限來保存用戶的信息，關(guān)閉瀏覽器后，驗(yàn)證是否能夠自動(dòng)登錄，若能登錄，則打印歡迎信息；否則跳轉(zhuǎn)到登錄頁面。

login.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%request.setCharacterEncoding("GB2312"); %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
 <base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" >
 
 <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" rel="external nofollow" rel="external nofollow" >
 -->
 <script type="text/javascript">
 window.onload = function(){
  //獲取submit
  var submit = document.getElementById("submit");
  var name = document.getElementById("name");
  //為submit綁定單擊響應(yīng)函數(shù)
  submit.onclick = function(){
  
  times = document.getElementsByName("time");
  var count=0;
  for(var i=0;i<times.length;i++){
   if(times[i].checked == true){
   count++;
   }
  }
  if(count>=2){
   alert("只能選擇一個(gè)選項(xiàng)");
   return false;
  }
  
  }; 
  
 };
 
 </script>
 </head>
 
 <body>
 <!-- 設(shè)置html頁面 -->
 <form action="sucess.jsp" method="post">
 用戶名：<input name="username" /><br/>
  <input type="checkbox" name="time" value="notSave" />不保存
  <input type="checkbox" name="time" value="aDay" />一天
  <input type="checkbox" name="time" value="aWeek" />一周
  <input type="checkbox" name="time" value="forever" />永久
  <br/><br/>
  <input type="submit" name="submit" id="submit" value="登錄"/>
 </form>
 <% 
 //讀取session值
 String val= (String)session.getAttribute("name");
 //如果session不存在
 if(val==null){
  val ="不存在";
 }
 out.print("當(dāng)前\""+val+"\"用戶可自動(dòng)登錄");
 %>

 </body>
</html>

sucess.jsp

%@ 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%>" rel="external nofollow" rel="external nofollow" >
 
 <title>My JSP 'show.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" >
 -->

 </head> 
 <body> 
<%
 //獲取username
 String name = request.getParameter("username");
 //判斷用戶名是否存在
 if(name != null && !name.trim().equals("")){ 
 String[] time = request.getParameterValues("time");
 //設(shè)置session值，便于login頁面讀取
 session.setAttribute("name", name);
 //設(shè)置Cookie
 Cookie Cookie = new Cookie("name",name);
 //根據(jù)提交選項(xiàng)設(shè)置cookie保存時(shí)間
 if(time != null){
  for(int i=0;i<time.length;i++){
  //不保存Cookie
  if(time[i].equals("notSave")){
   Cookie.setMaxAge(0); 
  }
  //保存一天Cookie
  if(time[i].equals("aDay")){
   Cookie.setMaxAge(60*60*24);
  }
  //保存一周Cookie
  if(time[i].equals("aWeek")){
   Cookie.setMaxAge(60*60*24*7);
  }
  //永久保存Cookie，設(shè)置為100年
  if(time[i].equals("forever")){
   Cookie.setMaxAge(60*60*24*365*100);
  }
  }
 }  
 
 //在客戶端保存Cookie
 response.addCookie(Cookie);
 } 
 else{%>
  <%--用戶名不存在則進(jìn)行判斷是否已有cookie --%>
 <%
 //獲取cookie
 Cookie[] cookies = request.getCookies();
 
 //cookie存在
 if(cookies != null && cookies.length > 0){
  for(Cookie cookie:cookies){
  //獲取cookie的名字
  String cookieName = cookie.getName();
  //判斷是否與name相等
  if(cookieName.equals("name")){
   //獲取cookie的值
   String value = cookie.getValue();
   name = value;
   }
  }
  }
 }
 if(name != null && !name.trim().equals("")){
 out.print("您好: " + name+"歡迎登錄");
 }
 else{//否則重定向到登錄界面
  out.print("您還沒有注冊，2秒后轉(zhuǎn)到注冊界面！");
 response.setHeader("refresh","2;url=login.jsp");
 %>
 如果沒有自動(dòng)跳轉(zhuǎn)，請點(diǎn)擊<a href="login.jsp" rel="external nofollow" >此處</a>進(jìn)行跳轉(zhuǎn)
 <%
 //response.sendRedirect("login.jsp");
 }
%>
 
 </body>
</html>

實(shí)現(xiàn)效果：

1.