Cookie对象详解

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 public Cookie(String name, String value) {
        validation.validate(name);//要求name唯一
        this.name = name;
        this.value = value;
    }

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package com.cookie.servlet;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.net.URLDecoder;
import java.net.URLEncoder;

/**
 * Cookie的注意点
 * 1.Cookie只在当前浏览器中有效
 * 2.Cookie不能存中文：
 * 如果一定要存中文，则需要URlEncode.encode()这个方法进行编码
 * 获取时通过URLDecoder.decode()进行解码
 * 3.如果出现同名的cookie对象则会覆盖
 * 4.cookie的存储数量是有上线的，不同浏览器的上限不同，cookie存储的大小是有限的大小为4kb
 *
 */
@WebServlet("/c04")
public class Cookie04 extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //Cookie存中文问题
        String name="name";
        String value="赵宇晖";
        //将中文通过URLEncoder
        name= URLEncoder.encode(name);
        value=URLEncoder.encode(value);
        //创建Cookie对象
        Cookie cookie=new Cookie(name,value);
        //响应Cookie
        response.addCookie(cookie);
        //获取Cookie时通过URLDecoder进行解码
        Cookie[] cookies=request.getCookies();
        //判断非空
       if (cookies!=null&&cookies.length>0){
            for (Cookie cook:cookies
                 ) {
                //解码
                System.out.println(URLDecoder.decode(cook.getName()));
                System.out.println(URLDecoder.decode(cook.getValue()));
            }
        }



    }
}

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package com.cookie.servlet;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.net.URLDecoder;
import java.net.URLEncoder;

/**
 * Cookie路径问题
 * 1./
 */
@WebServlet("/c05")
public class Cookie05 extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //当前项目下任何项目的任意资源都可以获取Cookie对象
        Cookie cookie01=new Cookie("cookie01","cookie01");
        //设置路径为/表示当前路径下任意项目都能访问到cookie对象
        cookie01.setPath("/");
        response.addCookie(cookie01);

        //默认的当前项目下可以获取Cookie对象(默认不设置cookie的path)
        //或者设置为当前站点名
        Cookie cookie02=new Cookie("cookie02","cookie02");
        cookie02.setPath("/zyh2");
        response.addCookie(cookie02);

        //指定项目下的资源可获取Cookie对象
        Cookie cookie03=new Cookie("cookie03","cookie03");
        //设置指定站点名
        cookie03.setPath("/zyh");
        response.addCookie(cookie03);

        //指定目录下的资源可获取Cookie对象；
        Cookie cookie04=new Cookie("cookie04","cookie04");
        cookie04.setPath("/zyh2/c02");
        response.addCookie(cookie04);




    }
}