一个网络文件管理系统，本系统提供的服务有：注册、登录、用户信息管理、上传文件、下载文件、删除上传的文件、共享文件、发送站内消息、接收消息和备忘录等服务。-A network file management system, this system provides services include: register, login, user information management, upload files, download files, delete, upload files, sh