java网络编程-UDP网络通信案例

package cn.mym.udp;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.util.Scanner;

public class UDPUser {

	static Scanner sinput = new Scanner(System.in);
	/**
	 *
title:main
	 *
function:UDP通信
	 *@author mym
	 *@param args
	 */
	public static void main(String[] args) {
		new GetMsg().start();
		new SendMsg().start();
	}
	
	static class GetMsg extends Thread{

		private DatagramSocket datagramSocket;
		//private ByteArrayInputStream byteArrayInputStream;
		//private DataInputStream dataInputStream;
		private byte[] bufs;
		private DatagramPacket p;
		private String msg;

		@Override
		public void run() {
			try {
				datagramSocket = new DatagramSocket(9991);
				
				bufs = new byte[1024];
				p = new DatagramPacket(bufs, bufs.length);
				//此时数据已经存放到buf中
				
				while(true){
					/*datagramSocket.receive(p);
					ByteArrayInputStream bis = new ByteArrayInputStream(bufs);
					DataInputStream dis = new DataInputStream(bis);
					msg = dis.readUTF();
					System.out.println("有人来信："+msg);*/
					
					datagramSocket.receive(p);
					ByteArrayInputStream bis=new ByteArrayInputStream(bufs);
					DataInputStream input=new DataInputStream(bis);
					System.out.println("有人来信:"+input.readUTF());
					
				}
				
			} catch (Exception e) {
				e.printStackTrace();
			}
			
		}
	}
	
	
	static class SendMsg extends Thread{

		private DatagramSocket datagramSocket;
		private ByteArrayOutputStream bos;
		private DataOutputStream dos;

		@Override
		public void run() {
			try {
				datagramSocket = new DatagramSocket(9990);
				String ip;
				
				while(true){
					bos = new ByteArrayOutputStream();
					dos = new DataOutputStream(bos);
					String s = sinput.next();
					dos.writeUTF(s);
					byte[] buf = bos.toByteArray();	//数据转换成字节数组
					System.out.println("请输入接收数据的ip：");
					ip = sinput.next();
					
					datagramSocket.send(new DatagramPacket(buf , buf.length, new InetSocketAddress(ip,9991)));
				}
				
				
				
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
			
		}
		
		
		
	}
	

}