学步园

1.发送

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.net.SocketException;

public class UDPSender {

	
	public static void main(String[] args){
		
		//1.创建要用来发送的本地地址对象
		SocketAddress localAddr = new InetSocketAddress("localhost", 13000);
		//2.创建发送的Socket对象
		try {
			DatagramSocket sender = new DatagramSocket(localAddr);
			
			String text = new String("今天星期天");
			byte[] buffer = text.getBytes();
			
			//3.发送数据的目标地址和端口
			SocketAddress dstAddr = new InetSocketAddress("localhost",14000);
			//4.创建要发送的数据包，指定内容，指定目标地址
			DatagramPacket pack = new DatagramPacket(buffer, buffer.length, dstAddr);
			//5.发送
			sender.send(pack);
			System.out.println("已发送");
		} catch (SocketException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		
				
	}
}

2.接收

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.net.SocketException;

public class UDPReceiver {

	public static void main(String[] args){
		
		//1.创建要用来发送的本地地址对象
		SocketAddress localAddr = new InetSocketAddress("localhost", 14000);
		//2.创建接受的服务器对象
		try {
			DatagramSocket receiver = new DatagramSocket(localAddr);
			//3.指定接收缓冲区,buffer太小将只能接受部分消息
			byte[] buffer = new byte[100];
			//4.创建接受数据包对象，指定接受大小
			DatagramPacket pack = new DatagramPacket(buffer, buffer.length);
			
			System.out.println("正在等待数据");
			//5.堵塞等待数据来临,如果收到数据,存入pack中
			receiver.receive(pack);
			
			SocketAddress sendAddr = pack.getSocketAddress();
			System.out.println("发送方的SocketAddr:"+sendAddr);
			
			String msg = new String(pack.getData()).trim();
			System.out.println("接受到的数据："+msg);
			
			
		} catch (SocketException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
}

3.组播群聊

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.UnknownHostException;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class MulticastClientFrame extends JFrame implements Runnable,ActionListener{

	
	private static final long serialVersionUID = 1L;

	private int port = 9999;
	private String ipAddr = "230.0.0.1";//组播IP地址
	private InetAddress dstAddress;//组播消息的目标地址
	private MulticastSocket sender;//本机组播发送端
	private JTextArea receiveArea;//接受数据显示框
	private JTextField nameField;//姓名框
	private JTextField inputField;//消息框
	JButton sendBu;//发送

	public MulticastClientFrame(){
		
		this.setTitle("组播");
		this.setSize(480, 300);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		try {
			dstAddress = InetAddress.getByName(ipAddr);
			sender = new MulticastSocket();
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		this.createUI();
		this.setVisible(true);
		//开启线程读取数据
		new Thread(this).start();
	}
	
	
	public void createUI(){
		this.setLayout(new FlowLayout(FlowLayout.LEFT));
		JLabel msgLabel = new JLabel("接受的消息:");
		receiveArea = new JTextArea(10,40);
		receiveArea.setLineWrap(true);
		JScrollPane recvScrollPane = new JScrollPane(receiveArea);
		
		JLabel nameLabel = new JLabel("姓名");
		nameField = new JTextField(5);
		JLabel sendLabel = new JLabel("发送消息：");
		inputField = new JTextField(20);
		
		sendBu = new JButton("发送");
		sendBu.addActionListener(this);
		
		this.add(msgLabel);
		this.add(recvScrollPane);
		this.add(nameLabel);
		this.add(nameField);
		this.add(sendLabel);
		this.add(inputField);
		this.add(sendBu);
	}
	
	public void run(){
		MulticastSocket receiver;
		try {
			receiver = new MulticastSocket(port);
			receiver.joinGroup(dstAddress);
			
			while(true){
				byte[] buffer = new byte[100];
				DatagramPacket pack = new DatagramPacket(buffer, buffer.length);
				receiver.receive(pack);
				
				String msg = new String(buffer).trim() + "\n";
				receiveArea.append(msg);

			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	
	public void sendMsg(String msg){
		
		byte[] data = msg.getBytes();
		DatagramPacket pack = new DatagramPacket(data, data.length, dstAddress, port);
		try {
			sender.send(pack);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	public void actionPerformed(ActionEvent e){
		if(e.getSource() == sendBu){
			String msg = nameField.getText()+":"+inputField.getText();
			sendMsg(msg);
		}
	}
	
	public static void main(String[] args){
		new MulticastClientFrame();
	}
	
}