<?php/*作者 : shyhero*/class Demo{    private static $ob=null;    private $name;    private $age;    private function __construct(){    }    public static function makeOb(){      var_dump($a);      if(self::$ob == null){        $c = __CLASS__;        self::$ob = new $c();      }      return self::$ob;    }    public function __set($tName,$value){      $this -> $tName = $value;    }}$a = Demo::makeOb();var_dump($a);