javaweb Cookie

本文链接： https://blog.csdn.net/weixin_43599377/article/details/102576732
Cookie就是服务器保存在客户端的数据,Cookie是由服务器创建，
package com.sheng.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;

//显示上一次访问的时间
//Cookie就是服务器保存在客户端的数据,Cookie是由服务器创建，
public class Damo4Cookie extends HttpServlet {
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		 //设置服务器端以utf-8编码进行输出
		 response.setCharacterEncoding("UTF-8");
		 response.setContentType("text/html;charset=UTF-8");
		 // 第一步.获得从客户端带过来的所有的Cookie:
		 Cookie[] cookies=request.getCookies();
		 PrintWriter out=response.getWriter();
		 //如果用户是第一次访问，那么得到cookies将是null
		 //第二步.从所有的Cookie中查找指定名称的Cookie：
		 if (cookies!=null) {
			 out.write("您上次访问的时间是：");
			 for (int i = 0; i < cookies.length; i++) {
				Cookie cookie=cookies[i];
				if (cookie.getName().equals("lastAccessTime")) {
					//第四步.记录当前的时间,并且利用Cookie将时间回写到浏览器端.  
					Long lastAccesTime=Long.parseLong(cookie.getValue());
					Date data=new Date(lastAccesTime);
					out.write(data.toLocaleString());
					System.out.println(cookies[0]);
				}
			}
		}else {
			out.write("这时您第一次访问本站");
		}
		 Cookie cookie=new Cookie("lastAccessTime", System.currentTimeMillis()+"");
		 //将cookie对象添加到response对象中，这样，服务器在输出response对象内容就会将cookie对象给输出出去
		 response.addCookie(cookie);
	}

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

}
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