    public static function encode($url)
    {
        $url = trim($url);

        if (empty($url) || !\is_string($url)) {
            return $url;
        }

        // 若已被编码的url，将被解码，再继续重新编码
        $url = urldecode($url);
        $encodeUrl = urlencode($url);
        $encodeUrl = str_replace(self::$entities, self::$replacements, $encodeUrl);

        return $encodeUrl;
    }