cookie的创建、发送与接收--会话(页码CK1)

最新推荐文章于 2024-04-28 21:19:44 发布

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最新推荐文章于 2024-04-28 21:19:44 发布

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分类专栏： Web 学习笔记 JAVA 文章标签： WEB cookie 会话

本文链接：https://blog.youkuaiyun.com/qq_40922845/article/details/105029485

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本文介绍了Cookie在Web中的工作原理，包括如何创建、发送和接收Cookie，特别是针对会话级别的Cookie。内容涵盖如何延长Cookie的生命周期，并提及了Session技术在验证码校验中的应用。

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cookie默认是会话级别的，如何延长cookie的持续时间呢

发送cookie

package cn.aynortechnology.cookie;

import java.io.IOException;
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 SendCookieServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//1.创建cookie对象
		Cookie cookie = new Cookie("name","wangwang");
		//2.设置Cookie再和护短的持久化时间，如果不设置持久化时间，cookie会存储在浏览器的内存中，浏览器关闭cookie存储的信息销毁，也就是会话级别的cookie
		cookie.setMaxAge(60*10);//十分钟	---时间设置成0代表删除该cookie
		//3.为Cookie设置携带的路径，如果不设置携带路径，那么该cookie会在与他同级的资源路径中携带信息
		//cookie.setPath("/WEB16/sendCookie");//当访问sendCookie资源时才携带这个cookie
		cookie.setPath("/WEB16");//当访问WEB16下的资源时都携带这个cookie
		//cookie.setPath("/");//当访问服务器下所有的资源都携带这个cookie
		//.将cookie中存储的信息发送到客户端----头
		response.addCookie(cookie);
	}

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

接受cookie

package cn.aynortechnology.cookie;

import java.io.IOException;
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 GetCookieServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//获得客户端携带的cookie数据
		Cookie[] cookies = request.getCookies();
		//通过cookie的名称获得想要的cookie
		for(Cookie cookie : cookies) {
			//获得cookie的名称
			String cookieName = cookie.getName();
			if(cookieName.equals("name")) {
				//获得该cookie的值
				String cookieValue = cookie.getValue();
				System.out.println(cookieValue);
			}
		}
	}

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

删除cookie

package cn.aynortechnology.cookie;

import java.io.IOException;
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 RemoveCookieServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//删除客户保存的name=zhangsan的cookie信息
		Cookie cookie = new Cookie("name", "zhangsan");
		//将path设置成与要删除的cookie的path一致
		cookie.setPath("/WEB16");
		//设置时间是0
		cookie.setMaxAge(0);
		//写
		response.addCookie(cookie);
	}

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

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package cn.aynortechnology.lastaccesstime;

import java.io.IOException;
import java.text.SimpleDateFormat;
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;

public class LastAccessTime extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		//获得当前时间
		Date date = new Date();
		SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
		String currentTime = format.format(date);
		
		//1.创建一个Cookie记录当前的最新访问时间
		Cookie cookie = new Cookie("lastAccessTime", currentTime);
		cookie.setMaxAge(60*10*500);
		response.addCookie(cookie);
		//2.获得客户端携带的cookie --- lastAccessTime
		String lastAccessTime = null;
		Cookie[] cookies = request.getCookies();
		if(cookies!=null) {
			for(Cookie coo : cookies) {
				if(coo.getName().equals("lastAccessTime")) {
					lastAccessTime = coo.getValue();
				}
			}
		}
		
		response.setContentType("text/html;charset=UTF-8");
		if(lastAccessTime==null) {
			response.getWriter().write("您是第一次访问");
		}else {
			response.getWriter().write("您上次访问的时间是："+lastAccessTime);
		}
	}

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

(页码CK1)cookie的创建、发送与接收–会话
 (页码CK2)session技术、完成验证码的校验–会话