采用套接字的连接方式编写一个程序，允许客户向服务器提出一个名字，如果这个文件存在，就把文件内容发送给客户，否则回答文件不存在。-Socket connection with the preparation of a program that allows customers to make a name server, if the file exists, put the document sent to the customer, otherwise the answer file does