JavaWeb小白笔记1—cookie

来源：互联网发布：卖男生帽子的淘宝店铺编辑：程序博客网时间：2024/05/02 01:12

package com.bttc;

import java.io.IOException;

import java.io.PrintWriter;

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 Wellcom extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

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

PrintWriter out = response.getWriter();

Cookie[] cookies = request.getCookies();

Cookie cookie = null;

int visitCount=0,visit = 0;

if(cookies!=null)

for (int i = 0; i < cookies.length; i++) {

cookie = cookies[i];

if (cookie.getName().equals("visitCount")) {

visitCount=Integer.valueOf(cookies[i].getValue());

System.out.println(i);

}

if(cookie.getName().equals("v")){

System.out.println("c "+i);

}

visitCount=visitCount+1;

visit ++;

Cookie cookie1 = new Cookie("visitCount", String.valueOf(visitCount));

Cookie c = new Cookie("v",String.valueOf(visit));

//cookie的有效期为1个月

cookie1.setMaxAge(24 * 60 * 60 * 30);

c.setMaxAge(60*60);

response.addCookie(cookie1);

response.addCookie(c);

out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");

out.println("<HTML>");

out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");

out.println(" <BODY>");

out.print("您是第"+visitCount+"次访问本站！");

out.println(" </BODY>");

out.println("</HTML>");

out.flush();

out.close();

}

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

doGet( request, response);

}

第一次执行时，cookies数组中没有数据，所以执行让visitcount+1，visit+1，创建两个对象并将visitcount和visit的值放到相应的位置（String格式存入），设置他们的存活时间，并把他们发送到客户端浏览器，保存在客户端计算机硬盘上。

访问时显示第一次访问，第二次执行，接收cookies数组，不为空时先找第0位置的数据的值进行判断（转为Integer）。

发送几个cookie对象，cookies数组的长度就为几。

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