COOKIE-优快云博客

本文链接：https://blog.youkuaiyun.com/Sunal_Sue/article/details/145704767

Cookie：

package com.demo.cookie;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

/**

* COOKIE的创建和发送

* new Cookie(name,value); name必须唯一

* @author 13554

*cookie 保存在浏览器客户端

*URL:http://localhost:8080/cookieProject/cookie1

@WebServlet("/cookie1")

public class Cookie1 extends HttpServlet {

@Override

protected void service(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) throws javax.servlet.ServletException, java.io.IOException{

//创建cookie

System.out.println("创建cookie1、cookie2");

Cookie cookie=new Cookie("name","Leo");

Cookie cookie2=new Cookie("password","Leo@900906");

cookie.setValue("Admin");

System.out.println("发送cookie1、cookie2");

//发送（响应）cookie

resp.addCookie(cookie);

resp.addCookie(cookie2);

}

package com.demo.cookie;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

/**

* 获取cookie

* request.getCookies():获取当前客户端当前项目的所有cookie

* @author 13554

*URL:http://localhost:8080/cookieProject/cookie2

@WebServlet("/cookie2")

public class Cookie2 extends HttpServlet {

@Override

protected void service(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) throws javax.servlet.ServletException, java.io.IOException{

System.out.println("获取所有cookie");

//获取当前客户端所有cookie

Cookie[] cookies=req.getCookies();

System.out.println("打印所有cookie");

for(Cookie cookie:cookies) {

System.out.println(cookie.getName());

System.out.println(cookie.getValue());

}

package com.demo.cookie;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

/**

Cookie设置到期时间 setMaxAge(int time)

time为负整数：默认值，表示只在浏览器内存中存活，关闭浏览器则失效

time为0：表示删除该cookie，cookie作废，无论是在浏览器内存中还是客户端硬盘上都会删除该cookie，如果之前有保存该cookie，可以通过setMaxAge(0)删除该cookie

time为正整数：表示存储的秒数，指定cookie的存活描述，无论打开、关闭浏览器，无论重启电脑与否，cookie必定在time为N秒后消失，N秒内都被服务器存在电脑硬盘里

@WebServlet("/cookie3")

public class Cookie3 extends HttpServlet {

@Override

protected void service(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) throws javax.servlet.ServletException, java.io.IOException{

// System.out.println("获取所有cookie");

// //获取当前客户端所有cookie

// Cookie[] cookies=req.getCookies();

// System.out.println("打印所有cookie");

// for(Cookie cookie:cookies) {

// System.out.println(cookie.getName());

// System.out.println(cookie.getValue());

// cookie.setMaxAge(-1);//默认值表示浏览器关闭前该cookie一直存在

// //cookie.setMaxAge(0);//表示删除该cookie

// //cookie.setMaxAge(1);//表示该cookie可以存在客户端硬盘上1秒钟，1秒后被删除

// }

//time为负整数：默认值，关闭浏览器则cookie失效

Cookie cookie1 =new Cookie("name","Sue");

cookie1.setMaxAge(-1);

resp.addCookie(cookie1);

//time为0：表示删除该cookie，cookie作废

Cookie cookie2 =new Cookie("age","31");

cookie2.setMaxAge(0);

resp.addCookie(cookie2);

//time为正整数：表示存储的秒数，浏览器会将数据存在指定磁盘中8秒

Cookie cookie3 =new Cookie("sex","Man");

cookie3.setMaxAge(8);//表示cookie 8秒后被删除

resp.addCookie(cookie3);

}

package com.demo.cookie;

import java.net.URLEncoder;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

/**

* COOKIE注意事项

* @author 13554

*URL:http://localhost:8080/cookieProject/cookie4

@WebServlet("/cookie4")

public class Cookie4 extends HttpServlet {

@Override

protected void service(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) throws javax.servlet.ServletException, java.io.IOException{

//1.cookie只保存在当前浏览器中，数据最终会存储在本地磁盘不能换电脑和浏览器

Cookie cookie1=new Cookie("name","Leo");

resp.addCookie(cookie1);

//2.cookie存中文问题：不支持中文，须通过URLEncoder.encode()编码，URLDecoder.decode()解码【该方法作废，不支持中文】

String name=URLEncoder.encode("姓名");

String value=URLEncoder.encode("雷檑");

Cookie cookie2=new Cookie(name,value);

resp.addCookie(cookie2);

//3.同名cookie会覆盖原来的cookie

Cookie cookie3=new Cookie("name","Stratovarius");

resp.addCookie(cookie3);

//4.cookie存放的数量不同浏览器的存储数量和大小都有限定，视浏览器而定 cookie一般大约4KB左右

//获取cookie

Cookie[] cookies=req.getCookies();

//打印cookie

for(Cookie cookie:cookies) {

System.out.println(cookie.getName()+" : "+cookie.getValue());

}

package com.demo.cookie;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

/**

* COOKIE设置路径

* 只有访问的URL路径中包含cooki的path值才能访问该cookie对象

* @author 13554

*URL:http://localhost:8080/cookieProject/cookie5

@WebServlet("/cookie5")

public class Cookie5 extends HttpServlet {

@Override

protected void service(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) throws javax.servlet.ServletException, java.io.IOException{

/*当前项目路径为cookieProject*/

Cookie cookie=new Cookie("name","Leo");

//NO.1 设置路径为：/ 表示当前服务器下任何项目都能拿到cookie对象

cookie.setPath("/");

//NO.2 设置路径为：/cookieProject 表示当前cookieProject项目下任何项目都能拿到cookie对象

cookie.setPath("/cookieProject");//【默认情况，可不设置】

//NO.3 设置路径为：/servletProject 表示servletProject项目下任何项目都能拿到cookie对象

cookie.setPath("/servletProject");//只能通过servletProject项目访问，就算是cookieProject项目产生的也不能访问

//NO.4 设置路径为：/cookieProject/cookie 表示只能/cookieProject/cookie 目录下的资源才能访问到cookie对象

cookie.setPath("/cookieProject/cookie");//比如同级目录cookie1目录下的项目就不能访问该cookie对象

resp.addCookie(cookie);

}