java udp获取广播ip地址代码

以下是Java实现UDP获取广播IP地址的示例代码：

import java.net.*;

public class UdpBroadcast {

  public static void main(String[] args) throws Exception {

    // 创建UDP Socket
    DatagramSocket socket = new DatagramSocket();

    // 设置广播地址
    InetAddress address = InetAddress.getByName("255.255.255.255");
    socket.setBroadcast(true);

    // 发送广播消息
    String message = "Hello, world!";
    DatagramPacket packet = new DatagramPacket(message.getBytes(), message.length(), address, 9999);
    socket.send(packet);

    // 接收广播消息
    byte[] buffer = new byte[1024];
    DatagramPacket receivePacket = new DatagramPacket(buffer, buffer.length);
    socket.receive(receivePacket);
    String receiveMessage = new String(receivePacket.getData(), 0, receivePacket.getLength());
    System.out.println("Received message: " + receiveMessage);

    // 关闭UDP Socket
    socket.close();
  }
}

在上述代码中，首先创建了一个UDP Socket，并设置广播地址为255.255.255.255，然后发送了一条广播消息，接着接收广播消息并输出接收到的消息内容，最后关闭UDP Socket。