用java实现网络用户机与服务器的连接。用户通过登陆用户端的界面，向服务器发送用户名及密码，待服务器端审核通过，服务器给出用户的答题请求，向客户端发送题目。-Network users with java and server connectivity. Users to visit the client interface to the server to send user name and password, to be approved server, the server gives