php 代理模式

<?phpheader("content-type:text/html;charset=utf-8");// ==================php  代理模式  =============================interface Proxy{     public function request();     public function display(); } class RealSubject{     public function request(){         echo "RealSubject request<br/>";     }     public function display(){         echo "RealSubject display<br/>";     } } class ProxySubject{     private $_subject = null;     public function __construct(){         $this->_subject = new RealSubject();     }     public function request(){         $this->_subject->request();     }     public function display(){         $this->_subject->display();     } } $objProxy = new ProxySubject(); $objProxy->request(); $objProxy->display();