package project1;  import java.awt.*; import java.awt.event.*; import java.io.*; import java.net.*;  import javax.swing.*;  public class Client {  private JFrame clientFrame;  private JLabel IPLabel;  private JLabel PortLabel;  private JLabel sayLabel;  private JLabel nicknameLabel;  private JTextField IPText;  private JTextField PortText;  private JTextField nicknameText;  private JTextField sayText;  private JButton connectButton;  private JButton nicknameButton;  private JButton sayButton;  private JPanel jPanelNorth;  private JPanel jPanelSouth0;  private JPanel jPanelSouth1;  private JPanel jPanelSouth2;  private JTextArea clientTextArea;  private JScrollPane scroller;  private BufferedReader reader;  private PrintWriter writer;  private String nickname;   public static void main(String args[]) {   Client aClient = new Client();   aClient.startUp();  }   // 初始化組件  public Client() {   nickname = "客戶端";    clientFrame = new JFrame();   jPanelNorth = new JPanel();   IPLabel = new JLabel("服務(wù)器IP", JLabel.LEFT);   IPText = new JTextField(10);   PortLabel = new JLabel("服務(wù)器端口", JLabel.LEFT);   PortText = new JTextField(10);   connectButton = new JButton("連接");   clientTextArea = new JTextArea();   scroller = new JScrollPane(clientTextArea);   jPanelSouth0 = new JPanel();   jPanelSouth1 = new JPanel();   jPanelSouth2 = new JPanel();   nicknameLabel = new JLabel("昵稱", JLabel.LEFT);   nicknameText = new JTextField(nickname, 30);   nicknameButton = new JButton("確認");   sayLabel = new JLabel("消息", JLabel.LEFT);   sayText = new JTextField(30);   sayButton = new JButton("確認");  }   // 構(gòu)建GUI  private void buildGUI() {   // 窗口的設(shè)置   clientFrame.setTitle("客戶端");   clientFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   clientFrame.setSize(550, 550);    // 北區(qū)的組件   jPanelNorth.add(IPLabel);   jPanelNorth.add(IPText);   jPanelNorth.add(PortLabel);   jPanelNorth.add(PortText);   jPanelNorth.add(connectButton);   clientFrame.getContentPane().add(BorderLayout.NORTH, jPanelNorth);    // 中間的組件   clientTextArea.setFocusable(false);   scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);   scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);   clientFrame.getContentPane().add(BorderLayout.CENTER, scroller);    // 南區(qū)的組件   jPanelSouth1.add(nicknameLabel);   jPanelSouth1.add(nicknameText);   jPanelSouth1.add(nicknameButton);   jPanelSouth2.add(sayLabel);   jPanelSouth2.add(sayText);   jPanelSouth2.add(sayButton);   jPanelSouth0.setLayout(new BoxLayout(jPanelSouth0, BoxLayout.Y_AXIS));   jPanelSouth0.add(jPanelSouth1);   jPanelSouth0.add(jPanelSouth2);   clientFrame.getContentPane().add(BorderLayout.SOUTH, jPanelSouth0);    // 設(shè)置窗口可見   clientFrame.setVisible(true);  }   // 客戶端運行  public void startUp() {   buildGUI();    // 接收服務(wù)器消息的線程   Runnable incomingReader = new Runnable() {    @Override    public void run() {     String message;     try {      while ((message = reader.readLine()) != null) {       clientTextArea.append(message + "/n");      }     } catch (Exception ex) {      ex.printStackTrace();     }    }   };    // 監(jiān)聽Connect按鈕，實現(xiàn)服務(wù)器的連接   connectButton.addActionListener(new ActionListener() {    @Override    public void actionPerformed(ActionEvent e) {     String aServerIP = IPText.getText();     String aServerPort = PortText.getText();      if (aServerIP.equals("") || aServerPort.equals("")) {      JOptionPane.showMessageDialog(clientFrame, "請輸入 完整的 IP和端口！");     } else {      try {       @SuppressWarnings("resource")       Socket clientSocket = new Socket(aServerIP, Integer.parseInt(aServerPort));       InputStreamReader streamReader = new InputStreamReader(clientSocket.getInputStream());       reader = new BufferedReader(streamReader);       writer = new PrintWriter(clientSocket.getOutputStream());        clientTextArea.append("服務(wù)器已連接.../n");        Thread readerThread = new Thread(incomingReader);       readerThread.start();      } catch (Exception ex) {       JOptionPane.showMessageDialog(clientFrame, "連接不上服務(wù)器!/n請確認 IP 和 端口 輸入正確。");      }     }    }   });    // 監(jiān)聽nickname，設(shè)置昵稱   ActionListener nicknameListener = new ActionListener() {    @Override    public void actionPerformed(ActionEvent e) {     String aText = nicknameText.getText();     if (!aText.equals("")) {      nickname = aText;     }    }   };   nicknameButton.addActionListener(nicknameListener);   nicknameText.addActionListener(nicknameListener);   nicknameText.addFocusListener(new FocusListener() {    @Override    public void focusGained(FocusEvent e) {    }     @Override    public void focusLost(FocusEvent e) {     String aText = nicknameText.getText();     if (!aText.equals("")) {      nickname = aText;     }    }   });    // 發(fā)送消息到服務(wù)器   ActionListener SayListener = new ActionListener() {    @Override    public void actionPerformed(ActionEvent e) {     String aText = sayText.getText();     if (aText.equals("")) {      JOptionPane.showMessageDialog(clientFrame, "內(nèi)容不能為空！");     } else {      try {       writer.println(nickname + "：" + aText);       writer.flush();      } catch (Exception ex) {       ex.printStackTrace();      }      sayText.setText("");     }    }   };   sayButton.addActionListener(SayListener);   sayText.addActionListener(SayListener);   }  } 

package project1;  import java.awt.*; import java.awt.event.*; import java.io.*; import java.net.*; import java.util.ArrayList; import java.util.Iterator; import javax.swing.*;  public class Server {  private JFrame serverFrame;  private JLabel portLabel;  private JLabel sayLabel;  private JLabel nicknameLabel;  private JTextField portText;  private JTextField sayText;  private JTextField nicknameText;  private JButton startButton;  private JButton sayButton;  private JButton nicknameButton;  private JPanel jPanelNorth;  private JPanel jPanelSouth0;  private JPanel jPanelSouth1;  private JPanel jPanelSouth2;  private JScrollPane scroller;  private JTextArea serverTextArea;  private ArrayList<PrintWriter> clientOutputStreams;  private String nickname;   public static void main(String[] args) {   Server aServer = new Server();   aServer.startUp();  }   // 初始化組件  public Server() {   nickname = "服務(wù)器";    serverFrame = new JFrame();   jPanelNorth = new JPanel();   portLabel = new JLabel("端口", JLabel.LEFT);   portText = new JTextField(30);   startButton = new JButton("開始");   serverTextArea = new JTextArea();   scroller = new JScrollPane(serverTextArea);   nicknameLabel = new JLabel("昵稱", JLabel.LEFT);   nicknameText = new JTextField(nickname, 30);   nicknameButton = new JButton("確認");   jPanelSouth0 = new JPanel();   jPanelSouth1 = new JPanel();   jPanelSouth2 = new JPanel();   sayLabel = new JLabel("消息", JLabel.LEFT);   sayText = new JTextField(30);   sayButton = new JButton("確認");  }   // 構(gòu)建GUI  private void buildGUI() {   // 窗口的設(shè)置   serverFrame.setTitle("服務(wù)器");   serverFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   serverFrame.setSize(550, 550);    // 北區(qū)的組件   jPanelNorth.add(portLabel);   jPanelNorth.add(portText);   jPanelNorth.add(startButton);   serverFrame.getContentPane().add(BorderLayout.NORTH, jPanelNorth);    // 中間的組件   serverTextArea.setFocusable(false);   scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);   scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);   serverFrame.getContentPane().add(BorderLayout.CENTER, scroller);    // 南區(qū)的組件   jPanelSouth1.add(nicknameLabel);   jPanelSouth1.add(nicknameText);   jPanelSouth1.add(nicknameButton);   jPanelSouth2.add(sayLabel);   jPanelSouth2.add(sayText);   jPanelSouth2.add(sayButton);   jPanelSouth0.setLayout(new BoxLayout(jPanelSouth0, BoxLayout.Y_AXIS));   jPanelSouth0.add(jPanelSouth1);   jPanelSouth0.add(jPanelSouth2);   serverFrame.getContentPane().add(BorderLayout.SOUTH, jPanelSouth0);    // 設(shè)置窗口可見   serverFrame.setVisible(true);  }   // 服務(wù)器運行  public void startUp() {   buildGUI();    // 監(jiān)聽Start按鈕，建立端口   ActionListener startListener = new ActionListener() {    @Override    public void actionPerformed(ActionEvent e) {     clientOutputStreams = new ArrayList<PrintWriter>();     String aPort = portText.getText();      if (aPort.equals("")) {      JOptionPane.showMessageDialog(serverFrame, "請輸入正確的端口號！");     } else {      try {       // 等待客戶端連接的線程       Runnable serverRunnable = new Runnable() {        @Override        public void run() {         ServerSocket serverSocket;         try {          serverSocket = new ServerSocket(Integer.parseInt(aPort));          serverTextArea.append("正在等待客戶端連接.../n");          while (true) {           Socket clientSocket = serverSocket.accept();           serverTextArea.append("客戶端已連接.../n");            PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());           clientOutputStreams.add(writer);            Thread t = new Thread(new ClientHandler(clientSocket));           t.start();          }         } catch (NumberFormatException | IOException e) {          e.printStackTrace();         }        }       };       Thread serverThread = new Thread(serverRunnable);       serverThread.start();      } catch (Exception ex) {       ex.printStackTrace();      }     }    }   };   startButton.addActionListener(startListener);   portText.addActionListener(startListener);    // 監(jiān)聽nickname，設(shè)置昵稱   ActionListener nicknameListener = new ActionListener() {    @Override    public void actionPerformed(ActionEvent e) {     String aText = nicknameText.getText();     if (!aText.equals("")) {      nickname = aText;     }    }   };   nicknameButton.addActionListener(nicknameListener);   nicknameText.addActionListener(nicknameListener);   nicknameText.addFocusListener(new FocusListener() {    @Override    public void focusGained(FocusEvent e) {    }     @Override    public void focusLost(FocusEvent e) {     String aText = nicknameText.getText();     if (!aText.equals("")) {      nickname = aText;     }    }   });    // 監(jiān)聽Say按鈕，發(fā)送消息   ActionListener SayListener = new ActionListener() {    @Override    public void actionPerformed(ActionEvent e) {     String aText = sayText.getText();     if (!aText.equals("")) {      aText = nickname + "：" + aText;      sendToEveryClient(aText);      serverTextArea.append(aText + "/n");      sayText.setText("");     } else {      JOptionPane.showMessageDialog(serverFrame, "內(nèi)容不能為空！");     }    }   };   sayButton.addActionListener(SayListener);   sayText.addActionListener(SayListener);  }   // 多客戶端的線程  public class ClientHandler implements Runnable {   BufferedReader bReader;   Socket aSocket;    public ClientHandler(Socket clientSocket) {    try {     aSocket = clientSocket;     InputStreamReader isReader = new InputStreamReader(aSocket.getInputStream());     bReader = new BufferedReader(isReader);    } catch (Exception ex) {     ex.printStackTrace();    }   }    @Override   public void run() {    String message;    try {     while ((message = bReader.readLine()) != null) {      sendToEveryClient(message);      serverTextArea.append(message + "/n");     }    } catch (Exception ex) {     ex.printStackTrace();    }   }  }   // 發(fā)送消息給所有客戶端的方法  private void sendToEveryClient(String message) {   Iterator<PrintWriter> it = clientOutputStreams.iterator();   while (it.hasNext()) {    try {     PrintWriter writer = (PrintWriter) it.next();     writer.println(message);     writer.flush();    } catch (Exception ex) {     ex.printStackTrace();    }   }  }  }