class Car{
    public static $_instance = null;
    private $name;

    private function __construct($name){
        $this->name = $name;
    }

    public static function getInstance($name){
        if(!self::$_instance){
            self::$_instance = new Car($name);
        }
        return self::$_instance;
    }

    public function getName(){
        return $this->name;
    }
}

$car = Car::getInstance("benchi");

$car1 = Car::getInstance("baoma");

print_r($car->getName());
print_r($car->getName()); // 输出 benchibenchi

  普通实例化类：

class Car{

    private $name;

     public function __construct($name){
         $this->name = $name;
    }

    public function getName(){
        return $this->name;
    }

}

$car = new Car("benchi");
$car1 = new Car("baoma");

print_r($car->getName());
print_r($car1->getName());  //输出 benchibaoma