cookie应用显示当前与之前时间

package com.neuedu.sevrlet;

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 ttc on 16-11-28.
*/
@WebServlet(name = "LastTimeServlet",urlPatterns = "/lasttime")
public class LastTimeServlet extends HttpServlet
{
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{

}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
boolean bIsFirstVisit = true;//假定当前是第一次访问
String strLastTime = "";

Cookie[] cookies = request.getCookies();
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("lasttime".equals(c.getName()))
{
bIsFirstVisit = false;
strLastTime = c.getValue();
}
}
}

response.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=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();

//将当前时间保存到cookie中
Cookie c = new Cookie("lasttime", curDate);
response.addCookie(c);

if(!bIsFirstVisit)
{
pw.print("当前时间为："+ curDate);

pw.print("上次的时间为："+ strLastTime);
}
else
{
pw.print("当前时间为："+ curDate);
}
}
}