普通静态绑定与后期静态绑定

1 普通静态绑定

<?php
class A
{
    public static function who()
    {
        echo __CLASS__.PHP_EOL;
    }
    public static function test()
    {
        self::who();
    }
}

class B extends A
{
    public static function who()
    {
        echo __CLASS__.PHP_EOL;
    }
}
B::test();
?>

输出：

 A

2 后期静态绑定

<?php
class A
{
    public static function who()
    {
        echo __CLASS__.PHP_EOL;
    }
    public static function test()
    {
        static::who();
    }
}

class B extends A
{
    public static function who()
    {
        echo __CLASS__.PHP_EOL;
    }
}
B::test();
?>

输出：

 B