JavaWeb之cookie学习笔记

原创

白鹭闲游 2023-05-30 16:20:18 ©著作权

文章标签 数据 java 服务器 文章分类 JavaScript 前端开发

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简介:

cookie用以将数据保存到客户端，等客户端再次向服务器发送数据时，服务器可以接受已保存的cookie用以执行相关操作

入门:

函数名	功能
new Cookie(String name, String value)	创建Cookie对象，绑定数据
response.addCookie(Cookie cookie)	发送Cookie对象
Cookie[] request.getCookies()	获取Cookie对象,拿到数据

示例

用以发送cookie

@WebServlet("/CookieDemo1")
public class CookieDemo1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 创建Cookie对象
        Cookie cookie = new Cookie("msg", "hello");
        // 发送Cookie
        response.addCookie(cookie);
    }

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

用以接受并打印Cookie

package cn.itcast.cookie;

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;

@WebServlet("/CookieDemo2")
public class CookieDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取Cookie
        Cookie[] cs = request.getCookies();
        if (cs != null) {
            for (Cookie c: cs) {
                String name = c.getName();
                String value = c.getValue();
                System.out.println(name + ':' + value);
            }
        }
    }

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

先后访问两个网址,控制台在第二次访问时输出msg:hello

JavaWeb之cookie学习笔记_服务器