yii2利用自带UploadedFile上传图片

public static function uploadFile($name)    {        $uploadedFile = UploadedFile::getInstanceByName($name);                if($uploadedFile === null || $uploadedFile->hasError)        {            return null;        }                $ymd = date("Ymd");                $save_path = dirname(Yii::$app->basePath).'\\web\\upload\\images\\'. $ymd . "\\";        $save_url = dirname(Yii::$app->homeUrl).'/upload/images/' . $ymd . "/";                if(! file_exists($save_path))        {            mkdir($save_path);        }               $file_name = $uploadedFile->getBaseName();        $file_ext = $uploadedFile->getExtension();                // 新文件名        $new_file_name = date("YmdHis") . '_' . rand(10000, 99999) . '.' . $file_ext;                $uploadedFile->saveAs($save_path . $new_file_name);               return ['path' => $save_path, 'url' => $save_url, 'name' => $file_name, 'new_name' => $new_file_name, 'ext' => $file_ext];    }