Java

In the server define an ArrayList to save all the clients that have made a connection and remove a client from the list once they disconnect.

package server1;

import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.InetAddress; import java.net.ServerSocket; import java.net.Socket; import java.net.SocketAddress; import java.net.UnknownHostException;

public class Server1Frame extends javax.swing.JFrame {

/** * Creates new form Server1Frame */ public Server1Frame() { initComponents(); }

pack();

private void jbtnStartServerActionPerformed(java.awt.event.ActionEvent evt) { // TODO add your handling code here: //put all the server code in a thread //to avoid locking the UI Thread serverThread = new SimpleServerThread(); serverThread.start(); }

@Override public void run() { ServerSocket server = null;

try{ server = new ServerSocket(9999); }catch(IOException ioe){ jTextArea1.setText("IOException:...... "+ ioe.getMessage()); return; } String hostAddress=""; String hostName=""; try { InetAddress hostInetAddress = InetAddress.getLocalHost(); hostAddress = hostInetAddress.getHostAddress(); hostName = hostInetAddress.getHostName(); }catch (UnknownHostException ex){ } jTextArea1.setText( "Server is ready: " + hostName+ " "+ hostAddress+":"+ "9999"); while(true){ try{ //get the client making a request Socket client = server.accept(); //display/log client info SocketAddress clientAddress = client.getRemoteSocketAddress(); jTextArea1.append(" Client socket address: "+ clientAddress); //start the client thread Thread thread = new ClientThread(client); thread.start(); }catch(IOException ioe){ }

}//end of while }//end of run

private void setVisible(boolean b) { throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates. } }//end of class: serverthread //thread to deal with client private class ClientThread extends Thread{ private Socket client; public ClientThread(Socket client){ this.client = client; }

@Override public void run() { PrintWriter out = null; //for the server to send //a resonse BufferedReader in = null; //for the server //to read client request try { out = new PrintWriter(client.getOutputStream(),true); in = new BufferedReader( new InputStreamReader(client.getInputStream())); //get client request String request= ""; String response=""; String command; do{ request = in.readLine(); //Assuming that request contains protocol commands: String[] tokens = request.split(""); if(tokens.length >= 1) command = tokens[0]; else command= "default";//any value is ok to send the switch to //default switch(command){ case "add": if(tokens.length==3){ try{ double x = Double.parseDouble(tokens[1].trim()); double y = Double.parseDouble(tokens[2].trim()); double total = x+y; response = x+" + "+y+" = "+ total; } catch(NumberFormatException nfe) { response="add command requires 2 values"; } } else response="add command requires 2 values"; break; case "bye": response ="Good night: you have been disconnected. Come backat a later time"; break; case "error": response="request not in the right format"; break; default: response = "Undefined command request"; break; } //send response back out.println(response); }while(!request.equals("bye")); //close if(in != null)in.close(); if(out != null)out.close(); }catch (IOException ex){ } }//end of run } // Variables declaration - do not modify private javax.swing.JScrollPane jScrollPane1; private javax.swing.JTextArea jTextArea1; private javax.swing.JButton jbtnStartServer; // End of variables declaration }

Start Server Display all Clients Start Server Display all Clients