public static function getUrlPrefix()
{
    if (empty(self::$_urlPrefix)) {
        self::$_urlPrefix = (self::isSecure() ? 'https' : 'http') 
            . '://' . (isset($_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : $_SERVER['SERVER_NAME'])
            . (in_array($_SERVER['SERVER_PORT'], array(80, 443)) ? '' : ':' . $_SERVER['SERVER_PORT']);
    }

    return self::$_urlPrefix;
}

问题在第五行$_SERVER['HTTP_HOST']本身带端口号