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PHP对象克隆clone用法示例

高洛峰

Lepaskan： 2023-03-03 20:02:01

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1167 orang telah melayarinya

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 &#39;<br>&#39;;
var_dump($obj_b);

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运行结果如下：

object(A)[1]
 public &#39;val&#39; => int 30
 public &#39;b&#39; =>
 object(B)[2]
  public &#39;val&#39; => int 40
 
object(A)[3]
 public &#39;val&#39; => int 20
 public &#39;b&#39; =>
 object(B)[2]
  public &#39;val&#39; => int 40

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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 &#39;<br>&#39;;
var_dump($obj_b);

Salin selepas log masuk

运行结果如下：

object(A)[1]
 public &#39;val&#39; => int 30
 public &#39;b&#39; =>
 object(B)[2]
  public &#39;val&#39; => int 40
 
object(A)[3]
 public &#39;val&#39; => int 20
 public &#39;b&#39; =>
 object(B)[4]
  public &#39;val&#39; => int 10

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希望本文所述对大家PHP程序设计有所帮助。

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