初步认识cookie

cookie是由服务器创建,客户端读取及保存它的

同类请求指的是资源路径相同

Cookie的默认路径绑定是所请求的资源路径绑定的，指定路径时必须要有项目名称（说明是哪个项目）

使用cookie时还要设置它的使用路径,一般是项目路径,比如

cookie = new Cookie("remember", username+":"+password);
cookie.setMaxAge(60*60*24*7);
cookie.setPath(request.getContextPath());
response.addCookie(cookie);//addCookie(cookie)方法会覆盖同名的cookie

package com.huawei.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;

/**
* Servlet implementation class TestCookie01
*/
public class TestCookie01 extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public TestCookie01() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub

/**
* Cookie 是一种在浏览器段存储信息的技术不宜在客户端存储大量数据信息不安全（可以加密）
*
* 它是由服务器生成回写到客户端在由客户端去决定该怎么处理这个数据
*
* 默认情况下是存在内存中的
* 默认情况下的作用范围是当前整个项目有效
*
*/

Cookie cookie = new Cookie("book", "Java");
Cookie cookie01 = new Cookie("book1", "Java1");
//要想存起来一定要设置他的有效期
//如果大于0 则会存储在文件中
//如果等于0 则会删除他自己
//如果小于0 则不会被存储起来而只是存在于客户端的内存中
cookie.setMaxAge(60*60);
//cookie.setMaxAge(0);
//设置生效范围只有给定路径以及给定路径的字路径有效
cookie.setPath("/TestCookie/test/test/123");
//是设置的同名不同值的相应消息头
response.addCookie(cookie);
response.addCookie(cookie01);
//response.
response.addHeader("Set-Cookie", "book2=javascript");

}

package com.huawei.cookie;

/**
* Servlet implementation class TestCookie02
*/
public class TestCookie02 extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public TestCookie02() {
super();
// TODO Auto-generated constructor stub
}

//得到cookie

String cookie = request.getHeader("Cookie");
System.out.println(cookie);
服务器端获取并解析cookie
Cookie []cookies = request.getCookies();
System.out.println(cookies.length);
for(Cookie c:cookies){
System.out.println(c.getName()+":"+c.getValue());
}
}

}

巴特西

初步认识cookie

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