MySQL과 Java를 이용하여 간단한 채팅방 기능을 구현하는 방법

  clientOutputStreams = new ArrayList<PrintWriter>();
  try {
     ServerSocket serverSock = new ServerSocket(5000);

     while (true) {
        Socket clientSocket = serverSock.accept();
        PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
        clientOutputStreams.add(writer);

        Thread t = new Thread(new ClientHandler(clientSocket));
        t.start();
        System.out.println("Got a connection");
     }
  } catch (Exception ex) {
     ex.printStackTrace();
  }

  Iterator<PrintWriter> it = clientOutputStreams.iterator();
  while (it.hasNext()) {
     try {
        PrintWriter writer = (PrintWriter) it.next();
        writer.println(message);
        writer.flush();
     } catch (Exception ex) {
        ex.printStackTrace();
     }
  }

  try {
     sock = clientSocket;
     InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
     reader = new BufferedReader(isReader);
  } catch (Exception ex) {
     ex.printStackTrace();
  }

  String message;
  try {
     while ((message = reader.readLine()) != null) {
        System.out.println("read " + message);
        ChatServer.tellEveryone(message);
     }
  } catch (Exception ex) {
     ex.printStackTrace();
  }

  buildGUI();
  setupNetworking();

  Frame frame = new Frame("Chat Client");
  messageArea = new TextArea();
  inputField = new TextField();
  sendButton = new Button("Send");

  sendButton.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent event) {
        try {
           String message = inputField.getText();
           writer.println(message);
           writer.flush();
           inputField.setText("");
        } catch (Exception ex) {
           ex.printStackTrace();
        }
     }
  });

  frame.add(messageArea, BorderLayout.CENTER);
  frame.add(inputField, BorderLayout.SOUTH);
  frame.add(sendButton, BorderLayout.EAST);
  frame.setSize(400, 300);
  frame.setVisible(true);

  try {
     sock = new Socket("localhost", 5000);
     InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
     BufferedReader reader = new BufferedReader(isReader);
     writer = new PrintWriter(sock.getOutputStream());
     Thread readerThread = new Thread(new IncomingReader(reader));
     readerThread.start();
  } catch (Exception ex) {
     ex.printStackTrace();
  }

  private BufferedReader reader;

  public IncomingReader(BufferedReader reader) {
     this.reader = reader;
  }

  public void run() {
     String message;
     try {
        while ((message = reader.readLine()) != null) {
           System.out.println("incoming " + message);
           messageArea.append(message + "

        }
     } catch (Exception ex) {
        ex.printStackTrace();
     }
  }