javaweb--Cookie

Cookie[] cookies=new Cookie();//获得cookie
cookie.getName();//获得cookie的名字
cookie.getValue();//获得cookie中的value
Cookie cookie=new Cookie("LastLoginTime",System.currentTimeMills()+"");//新建一个cookie
cookie.setMaxAge(24*60*60);//设置cookie的有效期
resp.addCookie(cookie);//响应给客户端一个cookie

package com.zhs.servlet;

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

public class DemoCookie extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("text/html");
        //服务端从客户端获取cookie
        Cookie[] cookies = req.getCookies();
        //判断cookie是否存在
        if(cookies!=null){
            PrintWriter out = resp.getWriter();
            out.write("上一次访问的时间是：");
            for (int i = 0; i < cookies.length; i++) {
                Cookie cookie=cookies[i];
                //获取cookie的名字
                String name = cookie.getName();
                if(name.equals("LastLoginTime")){
                    //获取cookie的值
                    Long value = Long.parseLong(cookie.getValue()) ;//强转为long型
                    Date date = new Date(value);//封装在date对象中
                    out.write(date.toGMTString());//// d MMM yyyy HH:mm:ss ‘GMT‘进行格式转换
                }

            }
        }
        //服务器给客户端相应cookie
        Cookie cookie = new Cookie("LastLoginTime", System.currentTimeMillis()+"");
        //设置cookie有效期
        cookie.setMaxAge(24*60*60);
        resp.addCookie(cookie);
       // resp.addCookie(new Cookie("LastLoginTime", System.currentTimeMillis()+""));
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

<servlet>
    <servlet-name>getcookie</servlet-name>
    <servlet-class>com.zhs.servlet.DemoCookie</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>getcookie</servlet-name>
    <url-pattern>/getcookie</url-pattern>
  </servlet-mapping>