Fatal error: Uncaught Error: Class 'think\Model' not found in /www/wwwroot/www.cn-5g-kaiyun.com/application/home/model/DownloadFile.php:22 Stack trace: #0 {main} thrown in /www/wwwroot/www.cn-5g-kaiyun.com/application/home/model/DownloadFile.php on line 22