关于文件夹的操作类，包括删除文件夹（可以直接删除其子目录与文件），获取文件夹文件列表，判断文件与文件夹是否存在，获取文件大小-Operation on the folder categories, including the deletion of folders (can be removed from the subdirectory and file), access to the folder list of files, documents and folders to determi