php的简略存在（魔术方法作用之一：容错）

name =$name;		$this->age  =$age;	}	//获取魔术方法	# @param  string   $name	public function __get($param){		// return $this->$param;		#允许被访问的属性		$allow = array('age');		if(in_array($param, $allow)){			return $this->$param;		}	}	//__set() 设置魔术方法	[email protected]  string $name	#param   string $val	public function __set($name,$val){		$allow = array('age','money');		if(in_array($name, $allow)){			$this->$name=$val;		}	}	// __isset() 判定数据	public function __isset($name){		return isset($this->$name);	}	//__unset 销毁数据	public function __unset($name){		//建立unset列表		$allow =array('tail');		if(in_array($name,$allow)){			echo 'unset running';			unset($this->$name);		}	}}//实例化$p = new Person('zp',21);$p->age = 200;echo $p->money = 200000000;$p->tail ="a";var_dump(isset($p->name));var_dump(isset($p->age));var_dump(isset($money));// var_dump(empty($tail));unset($p->tail);// var_dump($tail);