转载自网上的即时通讯 稍微修改了一下bug

package test3;
import java.awt.Button;
import java.awt.Color;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Label;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.swing.JOptionPane;

public class Chat {

public static void main(String[] args) {
new MyFrame();

new MyEvent();

Thread thread = new Thread(new MyRecevier());
thread.start();

}

}

class MySend {

public MySend() throws Exception {

DatagramSocket dSocket = new DatagramSocket(10000);
byte[] buf = ("from:" + InetAddress.getLocalHost().getHostAddress() + "\r\n" + MyEvent.myText)
.getBytes();

System.out.println("收到内容：" + MyEvent.myText);

DatagramPacket dPacket = new DatagramPacket(buf, buf.length,
InetAddress.getByName(MyEvent.myIp), 8888);// 自定义

dSocket.send(dPacket);
dSocket.close();

// 显示自己发的信息
// ----------------本机显示测试------------------//
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("YYYY/MM/dd HH:mm");
String date = simpleDateFormat.format(new Date());
MyFrame.receField.append(date + "\r\nME:" + MyEvent.myText + "\r\n");

}
}

class MyRecevier implements Runnable {

@SuppressWarnings("resource")
@Override
public void run() {

DatagramSocket dSocket = null;

try {
dSocket = new DatagramSocket(8888);
} catch (SocketException e1) {
e1.printStackTrace();
}
;

byte[] buf = new byte[1024];

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

while (true) {
try {
dSocket.receive(dPacket);
} catch (IOException e) {
e.printStackTrace();
}

String string = new String(dPacket.getData(), 0,
dPacket.getLength());

// ----------------本机显示测试------------------//
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("YYYY/MM/dd HH:mm");
String date = simpleDateFormat.format(new Date());
MyFrame.receField.append(date + "\r\n" + string + "\r\n");

}

}
}

class MyEvent {

static String myIp = "";
static String myText;
String myReceText;

public MyEvent() {

// 提交
MyFrame.btnPost.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {

myIp = MyFrame.ipField.getText().toString().trim();

String[] strings = myIp.split("\\.");
boolean t = true;

if (strings.length != 4) {
t = false;
JOptionPane.showMessageDialog(null, "请输入正确的IP地址！");
} else {
for (int i = 0; i < strings.length; i++) {

// 告知此字符串是否匹配给定的正则表达式。
if (!strings[i]
.matches("^[-+]?(([0-9]+)([.]([0-9]+))?|([.]([0-9]+))?)$")) {
t = false;
JOptionPane.showMessageDialog(null, "带有非数字字符！");
break;

} else if (Integer.parseInt(strings[i]) > 255
|| Integer.parseInt(strings[i]) < 0) {
t = false;
JOptionPane.showMessageDialog(null, "请输入正确的IP地址！");
break;
}

}
}
if (t) {
myIp = MyFrame.ipField.getText().toString().trim();
System.out.println("目标IP:" + myIp);
JOptionPane.showMessageDialog(null, "提交成功！");
}
}
});

// 清除
MyFrame.btnCancel.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {

MyFrame.inputField.setText(" ");

}
});

// 发送并清除编辑内容
MyFrame.btnSend.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {

myText = MyFrame.inputField.getText().toString().trim();

if (myIp.equals("")) {
JOptionPane.showMessageDialog(null, "请输入目标IP并提交！");
} else if (myText.equals("")) {
JOptionPane.showMessageDialog(null, "请输入内容再发送！");

} else {

System.out.println("发送内容：" + myText);
MyFrame.inputField.setText(" ");

try {

new MySend();

} catch (Exception e1) {
e1.printStackTrace();
}
}

}
});

// 刷新聊天记录
MyFrame.btnRecord.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {

}
});

}

}

class MyFrame {

Frame frame;
static Button btnSend, btnRecord, btnCancel, btnPost;
static TextArea inputField, recordField, receField;
static TextField ipField;

MyFrame() {
frame = new Frame("IP聊天");
frame.setSize(432, 500);
frame.setLayout(null);
frame.setLocation(400, 150);
frame.setResizable(false);
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
frame.setVisible(true);
frame.setBackground(Color.gray);

InputFrame();
}

public void InputFrame() {
Label label1 = new Label();
Label label2 = new Label("input IP :");
label1.setBounds(5, 10, 460, 200);
label2.setBounds(8, 465, 80, 30);

ipField = new TextField();
ipField.setBounds(85, 467, 148, 25);

inputField = new TextArea("", 5, 10, TextArea.SCROLLBARS_VERTICAL_ONLY);
recordField = new TextArea("", 5, 10, TextArea.SCROLLBARS_NONE);
receField = new TextArea("", 5, 10, TextArea.SCROLLBARS_VERTICAL_ONLY);
inputField.setBounds(5, 320, 420, 140);
inputField.setBackground(new Color(234,234,234));
recordField.setBounds(430, 30, 165, 430);
recordField.setBackground(new Color(234,234,234));
receField.setBounds(5, 30, 420, 285);
receField.setBackground(new Color(234,234,234));

inputField.setFocusable(true);
receField.setFocusable(false);
recordField.setFocusable(false);

ipField.setFont(new Font("Monospaced", Font.ITALIC, 15));
inputField.setFont(new Font("Monospaced", Font.ITALIC, 25));
receField.setFont(new Font("Monospaced", Font.ITALIC, 18));
recordField.setFont(new Font("Monospaced", Font.ITALIC, 15));

btnCancel = new Button("cancel");
btnSend = new Button("send");
btnRecord =
4000
new Button("Chalked Up");
btnPost = new Button("sumbit");

btnCancel.setBounds(295, 465, 60, 30);
btnSend.setBounds(360, 465, 60, 30);
btnRecord.setBounds(435, 465, 80, 30);
btnPost.setBounds(240, 465, 50, 30);

frame.add(inputField);
frame.add(receField);
frame.add(btnCancel);
frame.add(btnSend);
frame.add(btnPost);
frame.add(label1);
frame.add(label2);
frame.add(ipField);

}
}