记录用户上次访问时间（cookie和session）

package javapack;

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;

import utils.cookieutils;

public class countservlet extends HttpServlet {

/*
* (non-Javadoc)
* @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
* 显示登录成功的用户个数
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
int count=(Integer) this.getServletContext().getAttribute("count");
//获得从浏览器带来的所有cookies
Cookie[] cookies = request.getCookies();
//从数组中查找指定名称的cookie
Cookie cookie = cookieutils.findcookie(cookies, "lastvisit");
//创建一个cookie的对象
Cookie cook =new Cookie("lastvisit", ""+System.currentTimeMillis());//获取当前时间存入cookie中
/*cook.setPath("/J2EE");//设置cookie的有效路径
cook.setMaxAge(3600);//设置cookie的有效时间，以s为单位
*/		response.addCookie(cook);//保存到浏览器端
if(cookie==null){
//第一次访问
response.getWriter().println("<h1>您是第"+count+"位登录成功的用户<h1>");
}else{
long l=Long.parseLong(cookie.getValue());//将string转换成long
Date d=new Date(l);
response.getWriter().println("<h1>您是第"+count+"位登录成功的用户<h1>"+"您上次访问时间为"+d.toLocaleString());
}

}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);//post方式和get方式执行同一方法
}

}

package utils;

import javax.servlet.http.Cookie;

public class cookieutils {
public static Cookie findcookie(Cookie[] cookies,String name){
if(cookies==null){
return null;
}
else{
for(Cookie cookie:cookies){
if(name.equals(cookie.getName())){
return cookie;
}

}
return null;
}
}
}