【JSP开发】利用cookie返回上次登陆时间

实现一个页面，当用户登陆进去之后会显示上次用户登录的时间。

这个是主页，会显示用户上次登录的时间(原理是从cookie中提取)和记录这次用户访问
的时间并加入到cookie中。

CookieDemo1.java:
package cn.edu.cookie;


import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;


import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//带表网站首页
public class CookieDemo1 extends HttpServlet {


  public void doGet(HttpServletRequest request, HttpServletResponse 


response)
      throws ServletException, IOException {
          response.setCharacterEncoding("utf-8");
          response.setContentType("text/html;charset=utf-8");
          
          PrintWriter out=response.getWriter();
          out.print("<a href='/day07/CookieDemo2'>清除上次访问时间


</a><br/>");
          out.print("您上次访问时间是:");
          
          
          //获得用户的时间cookie
          Cookie cookies[]=request.getCookies();
          //第一次访问的时候Cookie是空的，就不用getcookie了
          for (int i = 0;cookies!=null && i < cookies.length; i++) {
            if(cookies[i].getName().equals("lastAccessTime")){
              long cookieValue=Long.parseLong(cookies


[i].getValue());//得到用户的上次访问时间(Long函数转成毫秒值)
              Date date=new Date(cookieValue);
              out.print(date.toLocaleString());
              
            }
      
    }
          
          //给用户返回最新的访问时间
          Cookie cookie=new Cookie


("lastAccessTime",System.currentTimeMillis()+"");
          cookie.setMaxAge(1*30*24*3600);
          cookie.setPath("/day07");
         
          response.addCookie(cookie);
  }


  public void doPost(HttpServletRequest request, HttpServletResponse 


response)
      throws ServletException, IOException {
       doGet(request,response);
  } 


}

清除上次访问时间的Servlet

CookieDemo2.java:

package cn.edu.cookie;


import java.io.IOException;


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


//给浏览器写一个MaxAge为0的Cookie(例如cookie名为name，就写一个叫name但是


MaxAge为0的Cookie)，就相当于删除相应的Cookie
public class CookieDemo2 extends HttpServlet {


  public void doGet(HttpServletRequest request, HttpServletResponse 


response)
      throws ServletException, IOException {
         Cookie cookie=new Cookie("lastAccessTime",System.currentTimeMillis


()+"");
         cookie.setMaxAge(0);//意味着让浏览器直接删除Cookie
         cookie.setPath("/day07");//删除cookie时，path必须与原cookie的path一


样
         response.addCookie(cookie);
         
         //response.sendRedirect("/day07/CookieDemo1");
  }


  public void doPost(HttpServletRequest request, HttpServletResponse 


response)
      throws ServletException, IOException {
        doGet(request,response);
  }


}