/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package MV3500Cohort2019JulySeptember.homework2; import java.io.*; import java.net.*; import java.util.Scanner; /** * * @author ljmm1 */ public class McCannServer { public static void main(String[] args) { try { // ServerSocket waits for a connection from a client. // Notice that it is outside the loop; ServerSocket // needs to be made only once. System.out.println("McCannServer has started..."); // it helps debugging to put this on console first //System.out.println("What is your name?"); ServerSocket serverSocket = new ServerSocket(2317); OutputStream os; PrintStream ps; InetAddress localAddress, remoteAddress; int localPort, remotePort; // Server is up and waiting (i.e. "blocked" or paused) // Loop, infinitely, waiting for client connections. // Stop the program somewhere else. while (true) { // block until connected to a client try (Socket clientConnection = serverSocket.accept()) { // Now hook everything up (i.e. set up the streams), Java style: os = clientConnection.getOutputStream(); ps = new PrintStream(os); Scanner keyboard = new Scanner(System.in); ps.println("What is your name?"); // this gets sent back to client! //String message = keyboard.nextLine(); // ps.println(message); // Print some information locally about the Socket connection. // This includes the port and IP numbers on both sides (the socket pair). localAddress = clientConnection.getLocalAddress(); remoteAddress = clientConnection.getInetAddress(); localPort = clientConnection.getLocalPort(); remotePort = clientConnection.getPort(); // My socket pair connection looks like this, to localhost: // Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54876 )) // Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54881 )) // Why is the first IP/port the same, while the second set has different ports? System.out.println("TcpExample3Server socket pair: (( " + localAddress.toString() + ", " + localPort + " ), ( " + remoteAddress.toString() + ", " + remotePort + " ))"); // Notice the use of flush() and try w/ resources. Without // the try w/ resources the Socket object may stay open for // a while after the client has stopped needing this // connection. try w/ resources explicitly ends the connection. ps.flush(); // like it or not, you're outta here! } } } catch (IOException e) { System.err.println("Problem with TcpExample3Server networking: " + e); // Provide more helpful information to user if exception occurs due to running twice at one time if (e instanceof java.net.BindException) { System.err.println("*** Be sure to stop any other running instances of programs using this port!"); } } } }