学步园

<?php<br /> class A {<br /> protected static $a;<br /> public static function init($value)<br /> {<br /> self::$a = $value;<br /> }<br /> public static function getA()<br /> {<br /> return self::$a;<br /> }<br /> }<br /> class B extends A {<br /> protected static $a; // redefine $a for own use<br /> // inherit the init() method<br /> public static function getA()<br /> {<br /> return self::$a;//此时 B::$a = '.B::getA();得不到值<br /> return parent::$a;//此时B::$a = '.B::getA();可以得到值<br /> }<br /> }<br /> A::init('xiexie');<br /> echo A::getA();<br /> B::init('lala');<br /> echo 'A::$a = '.A::getA().'; B::$a = '.B::getA();<br /> ?>