php中__CLASS__与get_class 的区别

<?php
/*
*  Author : Fanglor
*  Email  : Fanlor@163.com
*  Url    : www.skyleft.com
*  Date   : 2011-06-28 
*/
class Test__CLASS__ {
 
	var $url = '';
 
	function __construct () {
		$this->url = __CLASS__;
	}
 
	function get_url () {
		return $this->url;
	}
}
 
class ChildTest__CLASS__ extends Test__CLASS__{
 
	function __construct () {
		parent::__construct ();
	}
}
 
//测试
$Test =new ChildTest__CLASS__(); 
echo $Test->url;
echo "<br/>";
 
class Test_get_class {
 
	var $url = '';
 
	function __construct () {
		$this->url = get_class($this);
	}
 
	function get_url () {
		return $this->url;
	}
}
 
class ChildTest_get_class extends Test_get_class{
 
	function __construct () {
		parent::__construct ();
	}
}
 
//测试
$Test =new ChildTest_get_class(); 
echo $Test->url;