一个ftp客户端程序，前面已经上载了服务器端的程序，他们正好是一套，对于ftp的学习有很大的帮助，研究完这部分代码，你就完全是一个ftp高手了-an ftp client, as has already been uploaded to the server, they can be precisely set, ftp for the study will be very helpful to study completed this part of the code, you complet