便宜VPS网JSP全称Java Server Pages，是一种动态网页开发技术。它使用JSP标签在HTML网页中插入Java代码。标签通常以<%开头以%>结束。 JSP是一种Java servlet，主要用于实现Java web应用程序的用户界面部分。网页开发者们通过结合HTML代码、XHTML代码、XML元素以及嵌入JSP操作和命令来编写JSP。 本文将与大家分享，利用JSP实现用户七天内免登陆，这样可以减少输入密码等的繁琐，节约时间，使我们能更方便快捷的处理事项。
一、登陆页面：login.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<form action="LoginServlet" method="post">
用户名：<input type="text" name="username" value="${cookie.cook_name.value }"/><br/>
<input type="checkbox" name="chkCookie" value="7"/>记住我，7天内免登录<br/>
<input type="submit" value="登录"/><br/>
<a href="sessionUser.jsp" rel="external nofollow" >验证session</a>
<a href="cookieUser.jsp" rel="external nofollow" >验证cookie</a>
</form>
</body>
</html>
二、跳转页面：cookieUser.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<%
//从浏览器获取cookie
Cookie[] cookies = request.getCookies();String uname = null;
//判断语句条件小技巧
if(null != cookies){
for(Cookie cookie:cookies){
//遍历本地浏览器中的所有cookie
if(cookie.getName().equals("cook_name")){
//把cookie中的用户名取出
uname = cookie.getValue();
}
//out.print("<p>name: " + cookie.getName()+"</p>");
//out.print("<p>value: " + cookie.getValue()+"</p>");}
}
//判断cookie有没有失效
if(null != uname){
out.print("<p>用户名："+uname +"</p>");
}
else{
response.sendRedirect("login.jsp");
}
%>
</body>
</html>
三、Servlet文件：LoginServlet类
package com.servlet;
import java.io.IOException;
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 javax.servlet.http.HttpSession;/**
* Servlet implementation class LoginServlet
*/
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;/**
* @see HttpServlet#HttpServlet()
*/
public LoginServlet() {
super();
// TODO Auto-generated constructor stub
}/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//获取用户登录名
String username = request.getParameter("username");//获取7天内是否免登录
String day7 = request.getParameter("chkCookie");
int cookie_day = 1;
if(null != day7 && day7.equals("")){cookie_day = Integer.valueOf(day7);
}//创建cookie
Cookie cookie = new Cookie("cook_name",username);//设置Cookie有限期
//cookie.setMaxAge(6);//有效期6秒
cookie.setMaxAge(3600 * 24 * cookie_day);//设置7天免登录//写入cookie到浏览器
response.addCookie(cookie);
response.sendRedirect("cookieUser.jsp");}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}}
