使用 InetSocketAddress 创建 DatagramPacket，缺少构造函数答案

【问题标题】：Create DatagramPacket with InetSocketAddress, missing constructor使用 InetSocketAddress 创建 DatagramPacket，缺少构造函数
【发布时间】：2021-08-27 12:37:37
【问题描述】：

我正在尝试使用 Mutlicast 向多个客户端发送数据。我查看了文档：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);

我的问题是最后一行。 DatagramPacket 类没有这样的构造函数。这是文档中的错误还是我愚蠢？

【问题讨论】：

标签： java javadoc multicast

【解决方案1】：

似乎是 JavaDocs 中的一个错误。我的代码现在运行，用于本地多播：

// 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);

【讨论】：