import java.net.*; import java.io.*; import java.util.Date; /** * This program is a server that takes connection requests on * the port specified by the constant LISTENING_PORT. When a * connection is opened, the program sends the current time to * the connected socket. The program will continue to receive * and process connections until it is killed (by a CONTROL-C, * for example). Note that this server processes each connection * as it is received, rather than creating a separate thread * to process the connection. */ public class DateServer { public static final int LISTENING_PORT = 32007; public static void main(String[] args) { ServerSocket listener; // Listens for incoming connections. Socket connection; // For communication with the connecting program. /* Accept and process connections forever, or until some error occurs. (Note that errors that occur while communicating with a connected program are caught and handled in the sendDate() routine, so they will not crash the server.) */ try { listener = new ServerSocket(LISTENING_PORT); System.out.println("Listening on port " + LISTENING_PORT); while (true) { // Accept next connection request and handle it. connection = listener.accept(); sendDate(connection); } } catch (Exception e) { System.out.println("Sorry, the server has shut down."); System.out.println("Error: " + e); return; } } // end main() /** * The parameter, client, is a socket that is already connected to another * program. Get an output stream for the connection, send the current time, * and close the connection. */ private static void sendDate(Socket client) { try { System.out.println("Connection from " + client.getInetAddress().toString() ); Date now = new Date(); // The current date and time. PrintWriter outgoing; // Stream for sending data. outgoing = new PrintWriter( client.getOutputStream() ); outgoing.println( now.toString() ); outgoing.flush(); // Make sure the data is actually sent! client.close(); } catch (Exception e){ System.out.println("Error: " + e); } } // end sendDate() } //end class DateServer