使用 InetSocketAddress 创建 DatagramPacket，缺少构造函数

Question

I'm trying to send data with Mutlicast to multiple clients. I looked at the docs: https://docs.oracle.com/en/java/javase/16/docs/api/java.base/java/net/MulticastSocket.html#setNetworkInterface(java.net.NetworkInterface)

// join a Multicast group and send the group salutations
 ...
 String msg = "Hello";
 InetAddress mcastaddr = InetAddress.getByName("228.5.6.7");
 InetSocketAddress group = new InetSocketAddress(mcastaddr, port);
 NetworkInterface netIf = NetworkInterface.getByName("bge0");
 MulticastSocket s = new MulticastSocket(6789);

 s.joinGroup(group, netIf);
 byte[] msgBytes = msg.getBytes(StandardCharsets.UTF_8);
 DatagramPacket hi = new DatagramPacket(msgBytes, msgBytes.length,
                                        group, 6789);

My problem is the last line. The class DatagramPacket doesn't have such constructor. Is this a mistake in the Docs or am I dumb?

Answer 1

Seems to be a mistake in the JavaDocs. My code runs now, for local mutlicasting:

// join a Multicast group and send the group salutations
 ...
 String msg = "Hello";
 InetAddress mcastaddr = InetAddress.getByName("228.5.6.7");
 InetSocketAddress group = new InetSocketAddress(mcastaddr, 6789);
 NetworkInterface networkInterface = NetworkInterface.getByInetAddress(InetAddress.getByName("localhost"));
 MulticastSocket s = new MulticastSocket(6789);

 s.joinGroup(group, netIf);
 byte[] msgBytes = msg.getBytes(StandardCharsets.UTF_8);
 DatagramPacket hi = new DatagramPacket(msgBytes, msgBytes.length,
                                        group);