单例模式

  class Singleton {

      private static $_instance = null;
      private $name;
  　　private function __construct(){
        　$this->name = mt_rand(1,9);
  　　}
    public static function getInstance(){
        if(self::$_instance == null){
            self::$_instance = new Singleton();
        }
        return self::$_instance;
    }
    public function getName(){
        return $this->name;
    }

}
    $obj1 = Singleton::getInstance();
    $obj2 = Singleton::getInstance();
    //var_dump($obj1);
    echo $obj1->getName() . "\n";
    echo $obj2->getName() . "\n";