<?phpclass A { protected static $def = "123456"; public static function test() {echo get_class(new static); } public static function test2() {echo static::$def; }}class B extends A { protected static $def = "456789";}class C extends A { protected static $def = "abcdef";}echo B::test();echo "<br>";echo C::test();echo "<br>";echo B::test2();echo "<br>";echo C::test2();echo "<br>";echo A::test();echo "<br>";echo A::test2();echo "<br>";// 输出结果BC456789abcdefA123456