你不能.

object1 不是父级，而是容器.如果您想从 object2 访问 object1 函数，您必须有对 object1 的引用.

object1 isn't the parent, it's the container. If you want access to an object1 function from object2, you must have a reference to object1.

使用这种模式:

class class1 
{ 
   public $child; 
   public function __construct() 
   { 
      $this->child = new class2($this);
   }
} 

class class2 
{
   private $parent;
   public function __construct(class1 $parent) 
   {
      $this->parent = $parent; 
   }
}

这就是你要找的吗?