La définition et l'utilisation des méthodes magiques en PHP

<?php
 
class Magic
{
  public $var = &#39;test&#39;;
 
  //构造函数,在创建对象的时候调用
  public function __construct()
  {
    echo &#39;__construct called&#39;.PHP_EOL;
  }
 
  //某个对象的引用都被删除、对象被销毁、调用exit()后、脚本关闭时被调用
  public function __destruct()
  {
    echo &#39;__destruct called&#39;.PHP_EOL;
  }
 
  //当给不可访问或不存在属性赋值时被调用
  public function __set($name, $value)
  {
    echo $name.&#39;-&#39;.$value;
    echo &#39;__set called&#39;.PHP_EOL;
  }
 
  //读取不可访问或不存在属性时被调用
  public function __get($name)
  {
    echo $name;
    echo &#39;__get called&#39;.PHP_EOL;
  }
 
  //调用不可访问或不存在的方法时被调用
  public function __call($name, $arguments)
  {
    echo $name . &#39;-&#39; . implode(&#39;,&#39;, $arguments);
    echo &#39;__call called&#39;.PHP_EOL;
  }
 
  //调用不可访问或不存在的静态方法时被调用
  public static function __callStatic($name, $arguments)
  {
    echo $name . &#39;-&#39; . implode(&#39;,&#39;, $arguments);
    echo &#39;__callStatic called&#39;.PHP_EOL;
  }
 
  //对不可访问或不存在的属性调用isset()或empty()时被调用
  public function __isset($name)
  {
    echo $name;
    echo &#39;__isset called&#39;.PHP_EOL;
    return true;
  }
 
  //对不可访问或不存在的属性进行unset时被调用
  public function __unset($name)
  {
    echo $name;
    echo &#39;__unset called&#39;.PHP_EOL;
  }
 
  //serialize时被调用，当你不需要保存大对象的所有数据时很有用
  public function __sleep()
  {
    echo &#39;__sleep called&#39;.PHP_EOL;
    return array(&#39;var1111111111&#39;);
  }
 
  //unserialize时被调用，可用于做些对象的初始化操作
  public function __wakeup()
  {
    echo &#39;__wakeup called&#39;.PHP_EOL;
    $this->var = &#39;test after wakeup&#39;;
  }
 
  //当一个类被转换成字符串时被调用
  public function __toString()
  {
    return &#39;__toString called&#39;.PHP_EOL;
  }
 
  //进行对象clone时被调用，用来调整对象的克隆行为
  public function __clone()
  {
    echo &#39;__clone called&#39;.PHP_EOL;
  }
 
  //当以函数方式调用对象时被调用
  public function __invoke()
  {
    echo &#39;__invoke called&#39;.PHP_EOL;
  }
 
  //当调用var_export()导出类时，此静态方法被调用。用__set_state的返回值做为var_export的返回值。
  public static function __set_state($arr)
  {
    return &#39;__set_state called&#39;.PHP_EOL;
  }
 
  //当调用var_dump()打印对象时被调用（当你不想打印所有属性）适用于PHP5.6版本
  public function __debuginfo($arr)
  {
    echo &#39;__debuginfo called&#39;.PHP_EOL;
    return array(
      &#39;var&#39; => &#39;test fro __debuginfo&#39;
    );
  }
}
 
$m = new Magic(); //__construct()被调用
$m->not_exist_property = test; //__set()被调用
echo $m->not_exist_property;//__get()被调用
$m->abc(1,2,3); //__call()被调用
echo isset($m->not_exist_property); //__isset()被调用，返回bool值
unset($m->not_exist_property); //__unset()被调用
echo $tmp = serialize($m); //__sleep()被调用
unserialize($tmp); //__wakeup()被调用
$m1 = clone $m; //__clone()被调用，对象默认是引用传递，使用clone关键词则可实现对象复制
$m(); //__invoke()
eval( &#39;$m2 = &#39; . var_export ( $m , true ) . &#39;;&#39; );var_dump($m2);
var_dump($m);
//最后__destruct()被调用
 
/*
结果：
__construct called
not_exist_property-test__set called
not_exist_property__get called
abc-1,2,3__call called
not_exist_property__isset called
1not_exist_property__unset called
__sleep called
O:5:"Magic":1:{s:13:"var1111111111";N;}__wakeup called
__destruct called
__clone called
__invoke called
string(20) "__set_state called
"
class Magic#1 (1) {
 public $var =>
 string(4) "test"
}
__destruct called
__destruct called
 
 
*/