将文件上传至FTP或者是从指定FTP下载文件-Upload files to FTP or download files from the specified FTP

FTP 上传下载类。 包含文件夹命名，修改。 文件删除，重命名-FTP upload download class. Contains folder name, modification. Files deleted, renamed

其实，我只想要下载一份文件上传了一份比较低级的代码，望请见谅。-In fact, I just want to download a file before uploading a relatively low-level code program. Hope please forgive me. Thank you