Пример Клиент - Графичен интерфейс

Client avec nom et GUI

On va changer le protocole du dialogue entre le client et le serveur.

4.7.1 Client: Demande le nom d'utilisateur et l'envoie au serveur avant de faire le frame visible et de démarrer l'échange des messages.

import java.net.*;
import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.awt.event.*;

public class Client {
   BufferedReader in;
   PrintWriter out;
   InetAddress addr;
   Socket socket;
   String name;
   Gui g;
   Client(Frame f){
       g = new Gui(f);
   }
   class Gui{
       TextArea serv;
       TextField cl;
       Gui (Frame f){
           f.setLayout(new BorderLayout());
           serv = new TextArea(20,10);
           serv.setEditable(false);
           cl = new TextField(30);
           f.add("Center",serv);
           f.add("South",cl);
           cl.addActionListener(new SrvL());
       }
       class SrvL implements ActionListener{
           public void actionPerformed(ActionEvent e){
               try{
                   String st=cl.getText();
                   send(st);
                   cl.setText("");
                   serv.append(receive()+"\n");
               }
               catch (Exception ex){
                   System.out.println("exception: "+ex);
                   System.out.println("closing...");
                   try{
                       socket.close();
                   }
                   catch (Exception expt){
                       System.out.println(expt);
                   }
               }
           }
       }
   }
   public void init()throws IOException{
       try{
           String server = null;
           InetAddress addr = InetAddress.getByName(server);
           System.out.println("addr = " + addr);
           socket = new Socket(addr, MultiClientServerName.PORT);
           System.out.println("socket = " + socket);
           BufferedReader sin = new BufferedReader(
                   new InputStreamReader(System.in));
           in = new BufferedReader(
                   new InputStreamReader(socket.getInputStream()));
           // Output is automatically flushed
           // by PrintWriter:
           out = new PrintWriter(new BufferedWriter(
                   new OutputStreamWriter(socket.getOutputStream())),true);
           System.out.print("Your name: ");
           name = sin.readLine();
           System.out.println("sending name to server");
           out.println(name);
       }catch (Exception e){
           System.out.println("exception: "+e);
           System.out.println("closing...");
           socket.close();
       }
   }
   void send(String s){
       if(s.length()==0){
           out.println("END");
           System.out.println("closing...");
           try{
               socket.close();
           }
           catch (Exception expt){
               System.out.println(expt);
           }
           System.exit(0);
       }
       else out.println(name+": "+s);
   }
   String receive()throws IOException{
       return in.readLine();
   }
   public static void main(String[] args )throws IOException{
       JFrame frame =new JFrame();
       frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
       Client cl = new Client(frame);
       cl.init();
       frame.setTitle(cl.name);
       frame.setSize(300,500);
       frame.setVisible(true);
   }
}

4.7.2 Serveur: Démarre l'exécution du thread "ServeOneClient" par la réception du nom du client.

//: MultiClientServerName.java
// A server that uses multithreading to handle
// any number of clients with names.

import java.io.*;
import java.net.*;

class ServeOneClient extends Thread {
    private Socket socket;
    private BufferedReader in;
    private PrintWriter out;
    private String nameCl;
    public ServeOneClient(Socket s) throws IOException {
        socket = s;
        in = new BufferedReader(
                new InputStreamReader(
                        socket.getInputStream()));
        // Enable auto-flush:
        out = new PrintWriter( new BufferedWriter(
                new OutputStreamWriter(
                        socket.getOutputStream()
                        )
                ),
                true);
        // If any of the above calls throw an
        // exception, the caller is responsible for
        // closing the socket. Otherwise the thread
        // will close it.
        nameCl=""; //initialisation
        start();    // Calls run()
    }
    public void run() {
        try {
            nameCl=in.readLine();
        } catch (IOException e) { }

        System.out.println("new client "+nameCl );

        try {
            while (true) {
                String str = in.readLine();
                if (str.equals("END")) break;
                System.out.println("Echoing: " + str);
                out.println(str);
            }
            System.out.println("closing client "+ nameCl );
        } catch (IOException e) { }
        finally {
            try {
                socket.close();
            } catch(IOException e) {}
        }
    }
}

public class MultiClientServerName {
    static final int PORT = 8081;
    public static void main(String[] args) throws IOException {
        ServerSocket s = new ServerSocket(PORT);
        System.out.println("Server Started");
        try {
            while(true) {
                // Blocks until a connection occurs:
                Socket socket = s.accept();
                try {
                    new ServeOneClient(socket);
                } catch(IOException e) {
                    // If it fails, close the socket,
                    // otherwise the thread will close it:
                    socket.close();
                }
            }
        } finally {
            s.close();
        }
    }
}

4.7.3 Modifiez le serveur pour qu'il envoie dans le dialogue le nombre des clients connectés.