JAVA-WEB 会话技术 - (cookie演示-记录用户的最后访问时间)

cookieDemo Servlet

package demo;

import java.io.IOException;
import java.text.SimpleDateFormat;
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;

public class CookieDemo extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置编码
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		
		//获得当前时间
		//在发送cookie时Tomcat8.5是不允许使用空格的所以日期和时间中用_分割
		Date date = new Date();
		SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd_hh:mm:ss");
		String currentTime = sf.format(date);
		
		
		//获得用户名与密码
		String username = request.getParameter("username");
		String password = request.getParameter("password");
		System.out.println(username);
		System.out.println(password);
		//验证用户名与密码假设用户存在密码正确
		if("1234".equals(password)){
			System.out.println("登录成功。");
		}else {
			System.out.println("登陆失败");
		}
		
		Cookie coo = new Cookie("lastAccessTime", currentTime);
		//设置cookie保留10分钟
		coo.setMaxAge(60*10);
		//传递cookie到浏览器
		response.addCookie(coo);
		
		//从请求总获得cookie
		Cookie[] cookies = request.getCookies();
		String lastAccessTime = null;
		//遍历赋值lastAccessTime
		for (Cookie cookie : cookies) {
			if("lastAccessTime".equals(cookie.getName())) {
				lastAccessTime = cookie.getValue();
			}
		}
		//判断是否室第一次访问
		if(lastAccessTime != null) {
			response.getWriter().println(username + "上次登录时间："+  lastAccessTime);
		}else {
			response.getWriter().println(username + "是第一次登录");
		}
		
		
		
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

登录页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>








	

		用户名：
		

		密码：