PHP对象克隆clone用法示例

本文实例讲述了PHP对象克隆clone用法。分享给大家供大家参考，具体如下：

浅克隆：只是克隆对象中的非对象非资源数据，即对象中属性存储的是对象类型，则会出现克隆不完全

<?php
class B{
 public $val = 10;
}
class A{
 public $val = 20;
 public $b;
 public function __construct(){
  $this->b = new B();
 }
}
$obj_a = new A();
$obj_b = clone $obj_a;
$obj_a->val = 30;
$obj_a->b->val = 40;
var_dump($obj_a);
echo '<br>';
var_dump($obj_b);

运行结果如下：

object(A)[1]
 public 'val' => int 30
 public 'b' => 
 object(B)[2]
  public 'val' => int 40

object(A)[3]
 public 'val' => int 20
 public 'b' => 
 object(B)[2]
  public 'val' => int 40

深克隆：一个对象的所有属性数据都彻底的复制，需要使用魔术方法__clone()，并在里面实现深度克隆

<?php
class B{
 public $val = 10;
}
class A{
 public $val = 20;
 public $b;
 public function __construct(){
  $this->b = new B();
 }
 public function __clone(){
  $this->b = clone $this->b;
 }
}
$obj_a = new A();
$obj_b = clone $obj_a;
$obj_a->val = 30;
$obj_a->b->val = 40;
var_dump($obj_a);
echo '<br>';
var_dump($obj_b);

运行结果如下：

object(A)[1]
 public 'val' => int 30
 public 'b' => 
 object(B)[2]
  public 'val' => int 40

object(A)[3]
 public 'val' => int 20
 public 'b' => 
 object(B)[4]
  public 'val' => int 10

希望本文所述对大家PHP程序设计有所帮助。