java发送udp广播包

import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.SocketException;import java.net.UnknownHostException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Timer;public class UdpSend {    public void sendData()throws SocketException,UnknownHostException{    DatagramSocket ds = new DatagramSocket();// 创建用来发送数据报包的套接字String str = "hello";DatagramPacket dp = new DatagramPacket(str.getBytes(),str.getBytes().length,InetAddress.getByName("255.255.255.255"), 3001);// 构造数据报包，用来将长度为 length 的包发送到指定主机上的指定端口号try {ds.send(dp);} catch (IOException e) {e.printStackTrace();}ds.close();        }public static void main(String[] args) {    Timer timer = new Timer();    timer.schedule(new MyTask(), 1000, 1000);}    static class MyTask extends java.util.TimerTask{         @Override        public void run() {         UdpSend tt = new UdpSend();try {tt.sendData();} catch (SocketException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (UnknownHostException e) {// TODO Auto-generated catch blocke.printStackTrace();}        }    }}