"Clone Sheep" in php

Definition: Clone objectclone, that is, copying a new and identical object from an existing object, but the two are not the same object.

1. Object cloning is achieved through the clone keyword, namely: clone Object;

<?php
class Saler{
  	//属性
  	public $count;				
  	private $money;
}
//实例化
$s1 = new Saler();
$s1->count = 1;

//克隆
$s2 = clone $s1;
?>

2. The cloned object and the original object have two memory addresses, so they are two different objects

<?php
//接上述代码
$s2->count = 2;

echo $s1->count;		//1，没有变化
?>

3. The object will be instantiated when it is instantiated Automatically call the existing constructor method __construct(). Similarly, inside the class, PHP allows you to define a __clone() method. After the object is cloned, the newly cloned The object will automatically call

<?php
class Saler{
  	//属性
  	public $count;				
  	private $money;
    //克隆方法
    public function __clone(){
        var_dump($this);			//编号为2，代表是克隆出来的对象
        $this->count++;
    }
}
//实例化
$s1 = new Saler();
$s1->count = 1;

//克隆
$s2 = clone $s1;
?>

4. If the object is not allowed to be cloned, you can privatize the __clone() method (essentially, the object is not allowed to be cloned externally) )

<?php
class Saler{
  	//属性
  	public $count;				
  	private $money;
    //私有化克隆方法
    private function __clone(){}
}
//实例化
$s1 = new Saler();
$s1->count = 1;

//克隆
$s2 = clone $s1;			//致命错误：不允许对象在外部访问一个私有方法
?>

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