yii2图片上传

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];
    }