说明：  程序分为发送端和接收端。首先在传输文件数据之前，发送端会把将装有文件名称和文件长度等 信息的数据包发送至接收端。接收端收到文件名称和文件长度信息后会创建好空白文件。接着开始传输 文件数据。
(Program is divided into the sender and the receiver. First in a transmission file data before, the sender will put with the name of the document and file size, etc The packet of information to the receiver. The receiver file name and file information will create good length after blank document. Then began to transfer files data.)