<?php class Registry { private static $instance; private $request;//注册表的内容类 private function __construct(){}//本类，不可实例化 static function instance(){//单例类，通过这个方法返回实例 if (!isset(self::$instance)){self::$instance=new self();} return self::$instance; } function getRequest(){//返回注册的内容类 return $this->request; } function setRequest(request $request){//设置注册的内容类 $this->request=$request; } } class request{//被 注册的类 private $webname="WEB开发笔记"; private $url="www.chhua.com"; function getName(){ echo $this->url;//输出www.chhua.com } }//被注册的空类 //使用 $reg=Registry::instance(); $reg->setRequest(new request()); $request=$reg->getRequest(); $request->getName();//输出www.chhua.com ?>