java实现udp通讯的代码

/**
 * udp连接，用于动态ip, pos向255.255.255.255：5060发送请求即可
 * **/
public class UdpServer extends Thread implements Runnable {
  private final int MAX_LENGTH = 1024;
  private final int PORT = 5060;
  private DatagramSocket datagramSocket;
  
  public void run() {
    try {
      init();
      while(true){
        try {
          byte[] buffer = new byte[MAX_LENGTH];
          DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
          receive(packet);
          String receStr = new String(packet.getData(), 0 , packet.getLength());
          System.out.println("接收数据包" + receStr);
          byte[] bt = new byte[packet.getLength()];
          
          System.arraycopy(packet.getData(), 0, bt, 0, packet.getLength());
          System.out.println(packet.getAddress().getHostAddress() + "：" + packet.getPort() + "：" + Arrays.toString(bt));
          packet.setData(bt);
          response(packet);
          
        } catch (Exception e) {
          e.printStackTrace();
          LoggerUtil.error("udp线程出现异常：" + e.toString());
        }
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  public void receive(DatagramPacket packet) throws Exception {
    datagramSocket.receive(packet);
  }

  public void response(DatagramPacket packet) throws Exception {
    datagramSocket.send(packet);
  }
  
  /**
   * 初始化连接
   */
  public void init(){
    try {
      datagramSocket = new DatagramSocket(PORT);
      System.out.println("udp服务端已经启动！");
    } catch (Exception e) {
      datagramSocket = null;
      System.out.println("udp服务端启动失败！");
      e.printStackTrace();
    }
  }
}

/***
 * UDP Client端
 ***/
public class UdpClient {
  
  private String sendStr = "hello";
  private String netAddress = "255.255.255.255";
  private final int PORT = 5060;
  
  private DatagramSocket datagramSocket;
  private DatagramPacket datagramPacket;
  
  public UdpClient(){
    try { 
      datagramSocket = new DatagramSocket();
      byte[] buf = sendStr.getBytes();
      InetAddress address = InetAddress.getByName(netAddress);
      datagramPacket = new DatagramPacket(buf, buf.length, address, PORT);
      datagramSocket.send(datagramPacket);
      
      byte[] receBuf = new byte[1024];
      DatagramPacket recePacket = new DatagramPacket(receBuf, receBuf.length);
      datagramSocket.receive(recePacket);
      
      String receStr = new String(recePacket.getData(), 0 , recePacket.getLength());
      
　　　　　　　//获取服务端ip
      String serverIp = recePacket.getAdress();
    } catch (SocketException e) {
      e.printStackTrace();
    } catch (UnknownHostException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      // 关闭socket
      if(datagramSocket != null){
        datagramSocket.close();
      }
    }
  }
  
  public static void main(String[] args) {
    for (int i = 0; i < 100; i++) {
      new Thread(new Runnable() {
        @Override
        public void run() {
          UdpClient udpClient = new UdpClient();
        }
      }).start();
    }
  }
}