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import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.io.IOException;

import java.net.*;

public class GuiChat extends JFrame {

private static final int DEFAULT_PORT = 8899;

// 把主窗口分为NORTH、CEMTER和SOUTH三个部分

private JLabel stateLB; // 显示监听状态

private JTextArea centerTextArea; // 显示聊天记录

private JPanel southPanel; // 最下面的面板

private JTextArea inputTextArea; // 聊天输入框

private JPanel bottomPanel; // 放置 IP输入框，按钮等

private JTextField ipTextField; // IP输入框

private JTextField remotePortTF; // 端口号输入框

private JButton sendBT; // 发送按钮

private JButton clearBT; // 清除聊天记录按钮

private DatagramSocket datagramSocket; // 用于后面功能的实现

private void setUpUI() { // 初始化Swing窗口

// 初始化窗口

setTitle("GUI聊天");

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setSize(400, 400); // 设置窗口的大小

setResizable(false); // 窗口大小不可调整

setLocationRelativeTo(null); // 窗口居中

// 窗口的NORTH部分

stateLB = new JLabel("当前还未启动监听");

stateLB.setHorizontalAlignment(JLabel.RIGHT);

// 窗口的CENTER部分

centerTextArea = new JTextArea(); // 聊天记录显示区域

centerTextArea.setEditable(false);

centerTextArea.setBackground(new Color(211, 211, 211));

// 窗口的SOUTH部分

southPanel = new JPanel(new BorderLayout());

inputTextArea = new JTextArea(5, 20);// 内容输入区域

bottomPanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 5, 5));

ipTextField = new JTextField("127.0.0.1", 8);

remotePortTF = new JTextField(String.valueOf(DEFAULT_PORT), 3);

sendBT = new JButton("发送");

clearBT = new JButton("清屏");

bottomPanel.add(ipTextField);

bottomPanel.add(remotePortTF);

bottomPanel.add(sendBT);

bottomPanel.add(clearBT);

southPanel.add(new JScrollPane(inputTextArea), BorderLayout.CENTER);

southPanel.add(bottomPanel, BorderLayout.SOUTH);

// 添加窗口NORTH、CENTER、SOUTH部分的组件

add(stateLB, BorderLayout.NORTH);

add(new JScrollPane(centerTextArea), BorderLayout.CENTER);

add(southPanel, BorderLayout.SOUTH);

setVisible(true);

}

private void setListener() {

// 为sendBT按钮添加事件监听器

sendBT.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

// 获取发送的目标ip地址和端口号

final String ipAddress = ipTextField.getText();

final String remotePort = remotePortTF.getText();

// 判断ip地址和端口号是否为空

if (ipAddress == null || ipAddress.trim().equals("")

|| remotePort == null || remotePort.trim().equals("")) {

JOptionPane.showMessageDialog(GuiChat.this, "请输入IP地址和端口号");

return;

}

if (datagramSocket == null || datagramSocket.isClosed()) {

JOptionPane.showMessageDialog(GuiChat.this, "监听不成功");

return;

}

// 获得需要发送的内容

String sendContent = inputTextArea.getText();

byte[] buf = sendContent.getBytes();

try {

// 将发送的内容显示在自己的聊天记录中

centerTextArea.append("我对 " + ipAddress + ":" + remotePort

+ " 说：

" + inputTextArea.getText() + "

");

// 添加内容后，使滚动条自动滚动到最底端

centerTextArea.setCaretPosition(centerTextArea.getText()

.length());

// 发送数据

datagramSocket.send(new java代码入门基础 DatagramPacket(buf, buf.length,

InetAddress.getByName(ipAddress), Integer

.parseInt(remotePort)));

inputTextArea.setText("");

} catch (IOException e1) {

JOptionPane.showMessageDialog(GuiChat.this, "出错了,发送不成功");

e1.printStackTrace();

}

};

});

// 为clearBT按钮添加事件监听器

clearBT.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

centerTextArea.setText(""); // 清空聊天记录的内容

}

});

}

private void initSocket() {

int port = DEFAULT_PORT;

while (true) {

try {

if (datagramSocket != null && !datagramSocket.isClosed()) {

datagramSocket.close();

}

try { // 判断端口号是否在1-65535之间

port = Integer.parseInt(JOptionPane.showInputDialog(this,

"请输入端口号", "端口号", JOptionPane.QUESTION_MESSAGE));

if (port < 1 || port > 65535) {

throw new RuntimeException("端口号超出范围");

}

} catch (Exception e) {

JOptionPane.showMessageDialog(null,

"你输入的端口不正确，请输入1-65535之间的数");

continue; // 端口不正确重新填写

}

// 启动DatagramSocket

datagramSocket = new DatagramSocket(port);

startListen(); // 调用startListen方法

// 在stateLB中显示程序监听的端口号

stateLB.setText("已在 " + port + " 端口监听");

break;

} catch (SocketException e) { // 端口号被占用重新填写

JOptionPane.showMessageDialog(this, "端口已被占用，请重新设置端口");

stateLB.setText("当前还未启动监听");

}

}

}

private void startListen() {

new Thread() {

private DatagramPacket p;

public void run() {

byte[] buf = new byte[1024];

// 创建DatagramPacket

p = new DatagramPacket(buf, buf.length);

while (!datagramSocket.isClosed()) {

try {

datagramSocket.receive(p); // 接收聊天消息

// 添加到聊天记录框

centerTextArea.append(p.getAddress().getHostAddress()

+ ":"

+ ((InetSocketAddress) p.getSocketAddress())

.getPort() + " 对我说：

"

+ new String(p.getData(), 0, p.getLength())

+ "

");

// 使滚动条自动滚动到最底端

centerTextArea.setCaretPosition(centerTextArea

.getText().length());

} catch (IOException e) {

e.printStackTrace();

}

}

}

}.start();

}

public GuiChat() {

setUpUI();

initSocket();

setListener();

}

public static void main(String[] args) {

new GuiChat();

}