Cookie 设置cookie有效期及cookie常用方法

 

Demo03 :
 

package com.test.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 Demo03
 * 设置cookie有效期及cookie常用方法
 */
public class Demo03 extends HttpServlet {
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
			
		//1.发送客户端   可以给客户端返回多个cookie
		Cookie cookie = new Cookie("name", "lisi");
		response.addCookie(cookie);
		
		Cookie cookie1 = new Cookie("sex", "men");
		response.addCookie(cookie1);
		
		//2.获取带客户端的数据
		Cookie[] cookies = request.getCookies();
		if(cookies != null){
			for (Cookie cookie2 : cookies) {	
				System.out.println(cookie2.getName()+"="+cookie2.getValue());
			}
		}
		
		//3.cookie的有效期.默认情况下 7天
		//关闭浏览器后,cookie不存在.----->没有设置cookie的有效期
		/**expiry(有效) 以秒为单位
		* getMaxAge():返回以秒为单位的cookie的最大生存时间,默认情况下,-1表示该cookie将保留到浏览器关闭位置.
		* setMaxAge():以秒为单位
		* 正值表示cookie将在经过该值表示的秒数后过期.注意:该值是cookie过期的最大生存时间,不是cookie的当前生存时间.
		* 负值表示cookie不会被持久存储,将在web浏览器退出时删除.0会导致删除cookie[关闭浏览器,cookie就失效.默认值-1]
		*/
		//有效期设为7天
		cookie.setMaxAge(60 * 60 * 24 * 7);
		
		/**
		 * 扩展(常用的几个方法):
		 * 赋值新的值  cookie.setValue(newValue);
		 * 用于指定只有请求了指定的域名,才回带上该cookie.setDomain(domain);
		 * 只有访问该域名下的 uri 这个路径才会带cookie cookie.setPath(uri);
		 */
		
	}

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

}

web.xml:
 

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>CookieDemo</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <description></description>
    <display-name>Demo01</display-name>
    <servlet-name>Demo01</servlet-name>
    <servlet-class>com.test.cookie.Demo01</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Demo01</servlet-name>
    <url-pattern>/Demo01</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>Demo02</display-name>
    <servlet-name>Demo02</servlet-name>
    <servlet-class>com.test.cookie.Demo02</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Demo02</servlet-name>
    <url-pattern>/Demo02</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>Demo03</display-name>
    <servlet-name>Demo03</servlet-name>
    <servlet-class>com.test.cookie.Demo03</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Demo03</servlet-name>
    <url-pattern>/Demo03</url-pattern>
  </servlet-mapping>
</web-app>

 访问:

http://localhost:8081/CookieDemo/Demo03