static延迟静态绑定

 abstract class brand{
    public static function create()
    {
        return new static(); #指的是被调用的类而不是包含类
    }
    }


    class apple extends brand{

    }


    class vivo extends brand{

    }

    var_dump(apple::getGroup());die; #object(apple)#1 (0) { }
    }