php魔術方法有哪些

  //序列化
  class testSerialize{
   public $a = 10;
   public $b = 15;
   public $c = 20;
   function _construct(){
   $this->b = $this->a * 10;
   $this->c = $this->b * 2;
   } 
  }
$k = serialize(new testSerialize());
echo $k;//
out:  O:13:"testSerialize":3:{s:1:"a";i:10;s:1:"b";i:15;s:1:"c";i:20;}
$j = unserialize($k);

class testSerialize1{
   public $a = 10;
   public $b = 15;
   public $c = 20;
   function _construct(){
   $this->b = $this->a * 10;
   $this->c = $this->b * 2;
   } 
   function __sleep(){
   return $this->a;
   }
  }
$k = serialize(new testSerialize1());
echo $k;