Java Code Examples for java.nio.channels.DatagramChannel#join()

/** Try to listen to multicast messages
 *  @param udp UDP channel that should listen to multicast messages
 *  @param port Port to use
 *  @return Local multicast address, or <code>null</code> if no multicast support
 */
public static InetSocketAddress configureMulticast(final DatagramChannel udp, final int port)
{
    try
    {
        final NetworkInterface loopback = getLoopback();
        if (loopback != null)
        {
            final InetAddress group = InetAddress.getByName(PVASettings.EPICS_PVA_MULTICAST_GROUP);
            final InetSocketAddress local_broadcast = new InetSocketAddress(group, port);
            udp.join(group, loopback);

            logger.log(Level.CONFIG, "Multicast group " + local_broadcast + " using network interface " + loopback.getDisplayName());
            udp.setOption(StandardSocketOptions.IP_MULTICAST_LOOP, true);
            udp.setOption(StandardSocketOptions.IP_MULTICAST_IF, loopback);

            return local_broadcast;
        }
    }
    catch (Exception ex)
    {
        logger.log(Level.WARNING, "Cannot configure multicast support", ex);
    }
    return null;
}
 

@Test
public void TestServer() throws Exception {
    //接受组播和发送组播的数据报服务都要把组播地址添加进来
    String host = "239.239.239.88";//多播地址
    int port = 9998;
    InetAddress group = InetAddress.getByName(host);

    DatagramChannel channel = DatagramChannel.open(StandardProtocolFamily.INET);
    channel.bind(new InetSocketAddress(port));
    channel.join(group, Utils.getLocalNetworkInterface());
    ByteBuffer buffer = ByteBuffer.allocate(1024);
    SocketAddress sender = channel.receive(buffer);
    buffer.flip();
    byte[] data = new byte[buffer.remaining()];
    buffer.get(data);
    System.out.println(new String(data));

}
 

@Test
public void testSend() throws Exception {
    String host = "239.239.239.99";//多播地址
    int port = 9999;
    InetAddress group = InetAddress.getByName(host);
    String message = "test-multicastSocket";

    DatagramChannel channel = DatagramChannel.open(StandardProtocolFamily.INET);
    channel.configureBlocking(true);
    channel.bind(new InetSocketAddress(port));
    channel.join(group, Utils.getLocalNetworkInterface());

    InetSocketAddress sender = new InetSocketAddress("239.239.239.99", 4000);
    channel.send(ByteBuffer.wrap(message.getBytes()), sender);

    channel.close();
}
 

public static MarketData open(NetworkInterface multicastInterface,
        InetSocketAddress multicastGroup, InetSocketAddress requestAddress,
        long instrument) throws IOException {
    DatagramChannel channel = DatagramChannel.open(StandardProtocolFamily.INET);

    channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
    channel.bind(new InetSocketAddress(multicastGroup.getPort()));
    channel.join(multicastGroup.getAddress(), multicastInterface);
    channel.configureBlocking(false);

    DatagramChannel requestChannel = DatagramChannel.open(StandardProtocolFamily.INET);

    requestChannel.configureBlocking(false);

    return new MarketData(channel, requestChannel, requestAddress, instrument);
}
 

private synchronized DatagramChannel getChannel() throws IOException {
    if (channel == null || !channel.isOpen()) {
        if (shutdown.get()) {
            throw new IllegalStateException("Channel has been shut down");
        }
        ProtocolFamily protocolFamily = InternetProtocolUtils.getProtocolFamily(group.getAddress().getAddress());
        DatagramChannel _channel = selector.provider().openDatagramChannel(protocolFamily);
        _channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
        // bind to any-local before setting TTL
        int port = group.getAddress().getPort();
        if (protocolFamily == StandardProtocolFamily.INET) {
            _channel.bind(new InetSocketAddress(Inet4Address.getByName("0.0.0.0"), port));
        } else {
            _channel.bind(new InetSocketAddress(Inet6Address.getByName("[::]"), port));
        }
        int timeToLive = group.getTimeToLive();
        if (timeToLive != 1) {
            _channel.setOption(StandardSocketOptions.IP_MULTICAST_TTL, timeToLive);
        }

        for (NetworkInterface iface : networkInterfaces) {
            _channel.join(group.getAddress().getAddress(), iface);
        }

        _channel.configureBlocking(false);
        channel = _channel;
    }
    return channel;
}
 

/**
 * Receive messages. Invoke the message listener on each message. Continue
 * until a packet indicating the End of Session is received.
 *
 * @param multicastInterface the multicast interface
 * @param multicastGroup the multicast group
 * @param requestAddress the request address
 * @param listener a message listener
 * @throws IOException if an I/O error occurs
 */
public static void receive(NetworkInterface multicastInterface,
        InetSocketAddress multicastGroup, InetSocketAddress requestAddress,
        MessageListener listener) throws IOException {
    DatagramChannel channel = DatagramChannel.open(StandardProtocolFamily.INET);

    channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
    channel.bind(new InetSocketAddress(multicastGroup.getPort()));
    channel.join(multicastGroup.getAddress(), multicastInterface);
    channel.configureBlocking(false);

    DatagramChannel requestChannel = DatagramChannel.open(StandardProtocolFamily.INET);

    requestChannel.configureBlocking(false);

    StatusListener statusListener = new StatusListener();

    try (Selector selector = Selector.open();
            MoldUDP64Client client = new MoldUDP64Client(channel, requestChannel,
                requestAddress, listener, statusListener)) {
        SelectionKey channelKey = channel.register(selector, SelectionKey.OP_READ);

        SelectionKey requestChannelKey = requestChannel.register(selector, SelectionKey.OP_READ);

        while (statusListener.receive) {
            while (selector.select() == 0);

            Set<SelectionKey> selectedKeys = selector.selectedKeys();

            if (selectedKeys.contains(channelKey))
                client.receive();

            if (selectedKeys.contains(requestChannelKey))
                client.receiveResponse();

            selectedKeys.clear();
        }
    }
}
 

static DatagramChannel openClientChannel() throws IOException {
    DatagramChannel channel = DatagramChannel.open(StandardProtocolFamily.INET);

    channel.bind(null);
    channel.setOption(StandardSocketOptions.IP_MULTICAST_IF, loopbackInterface());
    channel.join(multicastGroup(), loopbackInterface());

    return channel;
}