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 the request of the user' s answer to the client to send the title.