php自动加载类

<?php

class CalssLoader
{
    public static function loader($classname)
    {
        $class_file = strtolower($classname).".php";
        if (file_exists($class_file)){
            require_once($class_file);
        }
    }
}
// 方法为静态方法
spl_autoload_register('CalssLoader::loader');
$test = new Test();

?>