首先，PHP对象clone参考资料：

 

Object Cloning

Creating a copy of an object with fully replicated properties is not always the wanted behavior. A good example of the need for copy constructors, is if you have an object which represents a GTK window and the object holds the resource of this GTK window, when you create a duplicate you might want to create a new window with the same properties and have the new object hold the resource of the new window. Another example is if your object holds a reference to another object which it uses and when you replicate the parent object you want to create a new instance of this other object so that the replica has its own separate copy.

An object copy is created by using the clone keyword (which calls the object's  method if possible). An object's  method cannot be called directly.

$copy_of_object = clone $object;

When an object is cloned, PHP 5 will perform a shallow copy of all of the object's properties. Any properties that are references to other variables will remain references.

 

void __clone ( void )

Once the cloning is complete, if a  method is defined, then the newly created object's  method will be called, to allow any necessary properties that need to be changed.

 

 

Example #1 Cloning an object

     instance = ++self::$instances;    }    public function __clone() {        $this->instance = ++self::$instances;    }}class MyCloneable{    public $object1;    public $object2;    function __clone()    {        // Force a copy of this->object, otherwise        // it will point to same object.        $this->object1 = clone $this->object1;    }}$obj = new MyCloneable();$obj->object1 = new SubObject();$obj->object2 = new SubObject();$obj2 = clone $obj;print("Original Object:\n");print_r($obj);print("Cloned Object:\n");print_r($obj2);?>

The above example will output:

Original Object:MyCloneable Object(    [object1] => SubObject Object        (            [instance] => 1        )    [object2] => SubObject Object        (            [instance] => 2        ))Cloned Object:MyCloneable Object(    [object1] => SubObject Object        (            [instance] => 3        )    [object2] => SubObject Object        (            [instance] => 2        ))

 

PHP中，其实用clone关键字加上__clone()便可以实现浅复制与深复制，__clone()方法就是那个抽象出来的接口。