Communication entre le serveur Java et le client

Je suis nouveau au concept de serveur en Java. J’ai mis en place un serveur très simple (la majeure partie a été copié depuis le net) et j’aimerais qu’il envoie à quel “statut” il est, mais j’aimerais qu’il ne l’envoie qu’une seule fois. Voici mon code, il pourrait être plus clair.

Serveur:

package components; import java.io.DataInputStream; import java.io.PrintStream; import java.io.IOException; import java.net.Socket; import java.net.ServerSocket; public class mainServer { // The server socket. private static ServerSocket serverSocket = null; // The client socket. private static Socket clientSocket = null; // This chat server can accept up to maxClientsCount clients' connections. private static final int maxClientsCount = 3; private static final clientThread[] threads = new clientThread[maxClientsCount]; public static void main(Ssortingng args[]) { // The default port number. int portNumber = 3333; if (args.length < 1) { System.out .println("Usage: java MultiThreadChatServer \n" + "Now using port number=" + portNumber); } else { portNumber = Integer.valueOf(args[0]).intValue(); } /* * Open a server socket on the portNumber (default 2222). Note that we can * not choose a port less than 1023 if we are not privileged users (root). */ try { serverSocket = new ServerSocket(portNumber); } catch (IOException e) { System.out.println(e); } /* * Create a client socket for each connection and pass it to a new client * thread. */ while (true) { try { clientSocket = serverSocket.accept(); int i = 0; for (i = 0; i < maxClientsCount; i++) { if (threads[i] == null) { (threads[i] = new clientThread(clientSocket, threads)).start(); break; } } if (i == maxClientsCount) { PrintStream os = new PrintStream(clientSocket.getOutputStream()); os.println("Server too busy. Try later."); os.close(); clientSocket.close(); } } catch (IOException e) { System.out.println(e); } } } } /* * The chat client thread. This client thread opens the input and the output * streams for a particular client, ask the client's name, informs all the * clients connected to the server about the fact that a new client has joined * the chat room, and as long as it receive data, echos that data back to all * other clients. When a client leaves the chat room this thread informs also * all the clients about that and terminates. */ class clientThread extends Thread { private DataInputStream is = null; private PrintStream os = null; private Socket clientSocket = null; private final clientThread[] threads; private int maxClientsCount; public clientThread(Socket clientSocket, clientThread[] threads) { this.clientSocket = clientSocket; this.threads = threads; maxClientsCount = threads.length; } public void run() { int maxClientsCount = this.maxClientsCount; clientThread[] threads = this.threads; try { /* * Create input and output streams for this client. */ is = new DataInputStream(clientSocket.getInputStream()); os = new PrintStream(clientSocket.getOutputStream()); os.println("Enter your name."); while (true) { String line = is.readLine(); if (line.startsWith("/quit")) { break; } if (line.startsWith("Home")) { os.println("Server in Home mode"); } if (line.startsWith("Search / Modify")){ System.out.println("Server in search and modify mo"); } } for (int i = 0; i < maxClientsCount; i++) { if (threads[i] != null && threads[i] != this) { threads[i].os.println("*** The user " + " is leaving the chat room !!! ***"); } } os.println("*** Bye " + " ***"); /* * Clean up. Set the current thread variable to null so that a new client * could be accepted by the server. */ for (int i = 0; i < maxClientsCount; i++) { if (threads[i] == this) { threads[i] = null; } } /* * Close the output stream, close the input stream, close the socket. */ is.close(); os.close(); clientSocket.close(); } catch (IOException e) { } } }

Principal: Donc, en ce moment, il envoie constamment le mot home à travers la sortie, puis le serveur renvoie la chaîne “Le serveur est en statut Home”, qui est ensuite imprimé. comment puis-je le faire pour ne l’envoyer qu’une seule fois, cela serait utile pour pouvoir détecter quel bouton est appuyé sur mon interface graphique et envoyer une commande au serveur quand il est.

 package components; //Import all libraries import java.awt.EventQueue; public class MainFrame implements Runnable { //declare Jpanel private static JFrame frmHome; // The client socket private static Socket clientSocket = null; // The output stream private static PrintStream os = null; // The input stream private static DataInputStream is = null; private static BufferedReader inputLine = null; private static boolean closed = false; public static void main(Ssortingng[] args){ // The default port. int portNumber = 3333; // The default host. Ssortingng host = "localhost"; System.out .println("Usage: java MultiThreadChatClient  \n" + "Now using host=" + host + ", portNumber=" + portNumber); /* * Open a socket on a given host and port. Open input and output streams. */ try { clientSocket = new Socket(host, portNumber); inputLine = new BufferedReader(new InputStreamReader(System.in)); os = new PrintStream(clientSocket.getOutputStream()); is = new DataInputStream(clientSocket.getInputStream()); } catch (UnknownHostException e) { System.err.println("Don't know about host " + host); } catch (IOException e) { System.err.println("Couldn't get I/O for the connection to the host " + host); } /* * If everything has been initialized then we want to write some data to the * socket we have opened a connection to on the port portNumber. */ if (clientSocket != null && os != null && is != null) { try { /* Create a thread to read from the server. */ new Thread(new MainFrame()).start(); while (!closed) { os.println("Home"); } /* * Close the output stream, close the input stream, close the socket. */ os.close(); is.close(); clientSocket.close(); } catch (IOException e) { System.err.println("IOException: " + e); } } } /* * Create a thread to read from the server. (non-Javadoc) * * @see java.lang.Runnable#run() */ public void run() { /* * Keep on reading from the socket till we receive "Bye" from the * server. Once we received that then we want to break. */ MainFrame window = new MainFrame(); MainFrame.frmHome.setVisible(true); Ssortingng responseLine; try { while ((responseLine = is.readLine()) != null) { System.out.println(responseLine); if (responseLine.indexOf("*** Bye") != -1) break; } closed = true; } catch (IOException e) { System.err.println("IOException: " + e); } } public MainFrame() { initialize(); } //function to make window visible void setVisible() { main(null); } private void initialize() { //Initialise Main window with 3 options. frmHome = new JFrame(); frmHome.setTitle("Home"); frmHome.setBounds(100, 100, 300, 372); frmHome.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frmHome.getContentPane().setLayout(null); frmHome.setResizable(false); JLabel lblWelcomeToSrs = new JLabel("Welcome to SRS"); lblWelcomeToSrs.setFont(new Font("Tahoma", Font.PLAIN, 14)); lblWelcomeToSrs.setBounds(86, 183, 112, 14); frmHome.getContentPane().add(lblWelcomeToSrs); //initialise all buttons and labels of window. JButton btnAdStu = new JButton("Add a student"); btnAdStu.setBounds(10, 207, 126, 23); btnAdStu.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { AddStudentFrame adus; try { adus = new AddStudentFrame(); adus.setVisible(); frmHome.setVisible(false); } catch (ParseException e) { e.printStackTrace(); } } }); frmHome.getContentPane().add(btnAdStu); JButton btnCheckStud = new JButton("Search / Modify"); btnCheckStud.setBounds(146, 207, 127, 23); btnCheckStud.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { SearchFrame searchFrame; searchFrame = new SearchFrame(); searchFrame.setVisible(); } }); frmHome.getContentPane().add(btnCheckStud); JLabel lblNewLabel = new JLabel(""); lblNewLabel.setBounds(0, 0, 0, 0); frmHome.getContentPane().add(lblNewLabel); JLabel lblCreatedByRmi = new JLabel("Created by R\u00E9mi Tuyaerts"); lblCreatedByRmi.setBounds(147, 318, 184, 14); frmHome.getContentPane().add(lblCreatedByRmi); JButton btnNewButton = new JButton("Complete List of Students"); btnNewButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { CompleteListFrame studentList = new CompleteListFrame(); frmHome.setVisible(false); studentList.setVisible(); } }); btnNewButton.setBounds(52, 241, 184, 23); frmHome.getContentPane().add(btnNewButton); // Button to set up the database JButton btnFillInDatabase = new JButton("Fill in database"); btnFillInDatabase.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { StudentStoring.student1(); StudentStoring.student2(); StudentStoring.student3(); StudentStoring.student4(); } }); btnFillInDatabase.setBounds(80, 276, 126, 23); frmHome.getContentPane().add(btnFillInDatabase); // wonderful pictures of his excellence design by Yasser JLabel lblNewLabel_1 = new JLabel(""); Image img = new ImageIcon(frmHome.getClass().getResource("/michaelchung.jpg")).getImage(); lblNewLabel_1.setIcon(new ImageIcon(img)); lblNewLabel_1.setBounds(80, 11, 120, 148); frmHome.getContentPane().add(lblNewLabel_1); } }

Vous devrez décider si vous souhaitez utiliser une seule connexion pour transférer plusieurs messages dans les deux sens ou si vous souhaitez établir une nouvelle connexion pour chaque message.

Pour conserver une seule connexion, ouvrez simplement le socket (côté client) et conservez-le quelque part. Ne le close() pas close() jusqu’à ce que vous n’ayez plus besoin de la connexion.

Si vous souhaitez utiliser une connexion par message, signalant effectivement la fin du message via close() , vous devez utiliser setSoLinger() du côté qui ferme la connexion. Cela donnera à l’autre bout le temps de lire les données en attente, de détecter la fin des données et de préparer la fin de la conversation sans rencontrer l’exception “socket closed”.