cookie应用之显示当前时间，上次时间

package com.neuedu.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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.text.SimpleDateFormat;
import java.util.Date;

/**
* Created by Administrator on 2016/11/28 0028.
*/
@WebServlet(name = "timeServlet",urlPatterns = "/lasttime")
public class timeServlet extends HttpServlet
{
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{

}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html;charset=utf-8");
response.setCharacterEncoding("utf-8");
//取得当前时间字符串
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
String curdate=sdf.format(new Date());
PrintWriter pw=response.getWriter();
Cookie [] cookies=request.getCookies();
String strtime="";
boolean isfirstvisit=true;//假定当前是第一次访问
if(cookies!=null){
for(Cookie c:cookies){
//看cookie中是否含有名称是lasttime的cookie，如果有，不是第一次访问（之前设置过这个cookie了）
//如果循环一圈都没有发现名称是lasttime的cookie，说明是第一次访问
if(
4000
"lasttime".equals(c.getName())){
isfirstvisit=false;
strtime=c.getValue();
}
}
}
//将当前时间保存到cookie中
Cookie c=new Cookie("lasttime",curdate);
response.addCookie(c);
if(!isfirstvisit){
pw.print("上次访问时间是"+curdate);
pw.print("当前时间是"+strtime);
}
else {
pw.print("当前时间是"+curdate);
}

}
}