Example usage for java.nio.channels DatagramChannel receive

Introduction

In this page you can find the example usage for java.nio.channels DatagramChannel receive.

Prototype

public abstract SocketAddress receive(ByteBuffer dst) throws IOException;

Source Link

Document

Receives a datagram via this channel.

Usage

From source file:MainClass.java

public static void main(String[] args) throws Exception {
    DatagramChannel channel = DatagramChannel.open();
    DatagramSocket socket = channel.socket();
    SocketAddress address = new InetSocketAddress(9999);
    socket.bind(address);/*from  w w w  .  java  2s  . c  o m*/
    ByteBuffer buffer = ByteBuffer.allocateDirect(65507);
    while (true) {
        SocketAddress client = channel.receive(buffer);
        buffer.flip();
        channel.send(buffer, client);
        buffer.clear();
    }
}

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From source file:UDPTimeServer.java

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

    int port = 37;

    ByteBuffer in = ByteBuffer.allocate(8192);
    ByteBuffer out = ByteBuffer.allocate(8);
    out.order(ByteOrder.BIG_ENDIAN);
    SocketAddress address = new InetSocketAddress(port);
    DatagramChannel channel = DatagramChannel.open();
    DatagramSocket socket = channel.socket();
    socket.bind(address);//  ww w  . ja  va 2s .com
    System.err.println("bound to " + address);
    while (true) {
        try {
            in.clear();
            SocketAddress client = channel.receive(in);
            System.err.println(client);
            long secondsSince1970 = System.currentTimeMillis();
            out.clear();
            out.putLong(secondsSince1970);
            out.flip();

            out.position(4);
            channel.send(out, client);
        } catch (Exception ex) {
            System.err.println(ex);
        }
    }
}

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From source file:Main.java

public static void main(String[] args) throws Exception {
    DatagramChannel client = null;
    client = DatagramChannel.open();

    client.bind(null);//from   w w w.  j  a  v  a  2 s.c  om

    String msg = "Hello";
    ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes());
    InetSocketAddress serverAddress = new InetSocketAddress("localhost", 8989);

    client.send(buffer, serverAddress);
    buffer.clear();
    client.receive(buffer);
    buffer.flip();
    int limits = buffer.limit();
    byte bytes[] = new byte[limits];
    buffer.get(bytes, 0, limits);
    String response = new String(bytes);
    System.out.println("Server  responded: " + response);
    client.close();
}

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From source file:Main.java

public static void main(String[] args) throws Exception {
    DatagramChannel server = null;
    server = DatagramChannel.open();
    InetSocketAddress sAddr = new InetSocketAddress("localhost", 8989);
    server.bind(sAddr);/*from  w  ww .  ja v  a2 s .com*/
    ByteBuffer buffer = ByteBuffer.allocate(1024);

    while (true) {
        System.out.println("Waiting for a  message  from" + "  a  remote  host at " + sAddr);
        SocketAddress remoteAddr = server.receive(buffer);
        buffer.flip();
        int limits = buffer.limit();
        byte bytes[] = new byte[limits];
        buffer.get(bytes, 0, limits);
        String msg = new String(bytes);

        System.out.println("Client at " + remoteAddr + "  says: " + msg);
        buffer.rewind();
        server.send(buffer, remoteAddr);
        buffer.clear();
    }
    //server.close();
}

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From source file:Main.java

public static void main(String[] args) throws Exception {
    MembershipKey key = null;//from   w  ww  .  j a va  2 s  . c o  m
    DatagramChannel client = DatagramChannel.open(StandardProtocolFamily.INET);

    NetworkInterface interf = NetworkInterface.getByName(MULTICAST_INTERFACE_NAME);
    client.setOption(StandardSocketOptions.SO_REUSEADDR, true);
    client.bind(new InetSocketAddress(MULTICAST_PORT));
    client.setOption(StandardSocketOptions.IP_MULTICAST_IF, interf);

    InetAddress group = InetAddress.getByName(MULTICAST_IP);
    key = client.join(group, interf);

    System.out.println("Joined the   multicast  group:" + key);
    System.out.println("Waiting for a  message  from  the" + "  multicast group....");

    ByteBuffer buffer = ByteBuffer.allocate(1048);
    client.receive(buffer);
    buffer.flip();
    int limits = buffer.limit();
    byte bytes[] = new byte[limits];
    buffer.get(bytes, 0, limits);
    String msg = new String(bytes);

    System.out.format("Multicast Message:%s%n", msg);
    key.drop();
}

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From source file:UDPTimeClient.java

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

    DatagramChannel channel = DatagramChannel.open();
    // port 0 selects any available port
    SocketAddress address = new InetSocketAddress(0);
    DatagramSocket socket = channel.socket();
    socket.setSoTimeout(5000);//ww w  .  j  av a2s.c om
    socket.bind(address);

    SocketAddress server = new InetSocketAddress("time.nist.gov", 37);
    ByteBuffer buffer = ByteBuffer.allocate(8192);
    // time protocol always uses big-endian order
    buffer.order(ByteOrder.BIG_ENDIAN);
    // Must put at least one byte of data in the buffer;
    // it doesn't matter what it is.
    buffer.put((byte) 65);
    buffer.flip();

    channel.send(buffer, server);

    buffer.clear();
    buffer.put((byte) 0).put((byte) 0).put((byte) 0).put((byte) 0);
    channel.receive(buffer);
    buffer.flip();
    long secondsSince1970 = buffer.getLong();

    System.out.println(secondsSince1970);
    channel.close();

}

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From source file:DaytimeServer.java

public static void main(String args[]) {
    try { // Handle startup exceptions at the end of this block
        // Get an encoder for converting strings to bytes
        CharsetEncoder encoder = Charset.forName("US-ASCII").newEncoder();

        // Allow an alternative port for testing with non-root accounts
        int port = 13; // RFC867 specifies this port.
        if (args.length > 0)
            port = Integer.parseInt(args[0]);

        // The port we'll listen on
        SocketAddress localport = new InetSocketAddress(port);

        // Create and bind a tcp channel to listen for connections on.
        ServerSocketChannel tcpserver = ServerSocketChannel.open();
        tcpserver.socket().bind(localport);

        // Also create and bind a DatagramChannel to listen on.
        DatagramChannel udpserver = DatagramChannel.open();
        udpserver.socket().bind(localport);

        // Specify non-blocking mode for both channels, since our
        // Selector object will be doing the blocking for us.
        tcpserver.configureBlocking(false);
        udpserver.configureBlocking(false);

        // The Selector object is what allows us to block while waiting
        // for activity on either of the two channels.
        Selector selector = Selector.open();

        // Register the channels with the selector, and specify what
        // conditions (a connection ready to accept, a datagram ready
        // to read) we'd like the Selector to wake up for.
        // These methods return SelectionKey objects, which we don't
        // need to retain in this example.
        tcpserver.register(selector, SelectionKey.OP_ACCEPT);
        udpserver.register(selector, SelectionKey.OP_READ);

        // This is an empty byte buffer to receive emtpy datagrams with.
        // If a datagram overflows the receive buffer size, the extra bytes
        // are automatically discarded, so we don't have to worry about
        // buffer overflow attacks here.
        ByteBuffer receiveBuffer = ByteBuffer.allocate(0);

        // Now loop forever, processing client connections
        for (;;) {
            try { // Handle per-connection problems below
                // Wait for a client to connect
                selector.select();/*from  www  . j  a va 2s .co m*/

                // If we get here, a client has probably connected, so
                // put our response into a ByteBuffer.
                String date = new java.util.Date().toString() + "\r\n";
                ByteBuffer response = encoder.encode(CharBuffer.wrap(date));

                // Get the SelectionKey objects for the channels that have
                // activity on them. These are the keys returned by the
                // register() methods above. They are returned in a
                // java.util.Set.
                Set keys = selector.selectedKeys();

                // Iterate through the Set of keys.
                for (Iterator i = keys.iterator(); i.hasNext();) {
                    // Get a key from the set, and remove it from the set
                    SelectionKey key = (SelectionKey) i.next();
                    i.remove();

                    // Get the channel associated with the key
                    Channel c = (Channel) key.channel();

                    // Now test the key and the channel to find out
                    // whether something happend on the TCP or UDP channel
                    if (key.isAcceptable() && c == tcpserver) {
                        // A client has attempted to connect via TCP.
                        // Accept the connection now.
                        SocketChannel client = tcpserver.accept();
                        // If we accepted the connection successfully,
                        // the send our respone back to the client.
                        if (client != null) {
                            client.write(response); // send respone
                            client.close(); // close connection
                        }
                    } else if (key.isReadable() && c == udpserver) {
                        // A UDP datagram is waiting. Receive it now,
                        // noting the address it was sent from.
                        SocketAddress clientAddress = udpserver.receive(receiveBuffer);
                        // If we got the datagram successfully, send
                        // the date and time in a response packet.
                        if (clientAddress != null)
                            udpserver.send(response, clientAddress);
                    }
                }
            } catch (java.io.IOException e) {
                // This is a (hopefully transient) problem with a single
                // connection: we log the error, but continue running.
                // We use our classname for the logger so that a sysadmin
                // can configure logging for this server independently
                // of other programs.
                Logger l = Logger.getLogger(DaytimeServer.class.getName());
                l.log(Level.WARNING, "IOException in DaytimeServer", e);
            } catch (Throwable t) {
                // If anything else goes wrong (out of memory, for example)
                // then log the problem and exit.
                Logger l = Logger.getLogger(DaytimeServer.class.getName());
                l.log(Level.SEVERE, "FATAL error in DaytimeServer", t);
                System.exit(1);
            }
        }
    } catch (Exception e) {
        // This is a startup error: there is no need to log it;
        // just print a message and exit
        System.err.println(e);
        System.exit(1);
    }
}

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From source file:me.schiz.jmeter.ring.udp.EventLoopRunnable.java

private void readCallback(DatagramChannel dc) throws IOException {
    Token t = ring.get(dc);//from www  .  j  a  va  2  s  .com
    t.lock.lock();
    try {
        t.remote = dc.receive(byteBuffer);
        //EOF
        if (t != null) {
            if (t.timeout != null)
                t.timeout.cancel();
        }
        byteBuffer.flip();
        if (t.sampleResult != null) {
            t.sampleResult.sampleEnd();
            byte[] res = Charset.defaultCharset().decode(byteBuffer).toString().getBytes();
            if (t.ishex) {
                t.sampleResult.setResponseData(String.valueOf(Hex.encodeHex(res, true)).getBytes());
            } else {
                t.sampleResult.setResponseData(res);
            }

            while (!t.queue.offer(t.sampleResult)) {
            }
            t.sampleResult = null;
            t.queue = null;
        } else {
            log.warn("have response without request");
        }
        ring.release(t.id);
    } catch (IOException e) {
        t.sampleResult.setResponseCode(e.toString());
        t.sampleResult.setSuccessful(false);
        while (!t.queue.offer(t.sampleResult)) {
        }
    } finally {
        t.lock.unlock();
        byteBuffer.clear();
    }
}

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From source file:com.offbynull.portmapper.common.UdpCommunicator.java

@Override
protected void run() throws Exception {
    ByteBuffer recvBuffer = ByteBuffer.allocate(1100);

    while (true) {
        selector.select();/*from w w  w  .java 2 s.  c om*/
        if (stopFlag) {
            return;
        }

        for (DatagramChannel channel : sendQueue.keySet()) {
            if (!sendQueue.get(channel).isEmpty()) {
                channel.register(selector, SelectionKey.OP_READ | SelectionKey.OP_WRITE);
            } else {
                channel.register(selector, SelectionKey.OP_READ);
            }
        }

        for (SelectionKey key : selector.selectedKeys()) {
            if (!key.isValid()) {
                continue;
            }

            DatagramChannel channel = (DatagramChannel) key.channel();

            if (key.isReadable()) {
                recvBuffer.clear();
                InetSocketAddress incomingAddress = (InetSocketAddress) channel.receive(recvBuffer);
                recvBuffer.flip();
                for (UdpCommunicatorListener listener : listeners) {
                    try {
                        listener.incomingPacket(incomingAddress, channel, recvBuffer.asReadOnlyBuffer());
                    } catch (RuntimeException re) { // NOPMD
                        // do nothing
                    }
                }
            } else if (key.isWritable()) {
                LinkedBlockingQueue<ImmutablePair<InetSocketAddress, ByteBuffer>> queue = sendQueue
                        .get(channel);
                ImmutablePair<InetSocketAddress, ByteBuffer> next = queue.poll();

                if (next != null) {
                    try {
                        channel.send(next.getValue(), next.getKey());
                    } catch (RuntimeException re) { // NOPMD
                        // do nothing
                    }
                }
            }
        }
    }
}

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From source file:org.apache.axis2.transport.udp.IODispatcher.java

private void receive(Endpoint endpoint, DatagramChannel channel) {
    try {/*from w w  w  . ja v  a2  s . co m*/
        byte[] data = new byte[endpoint.getMaxPacketSize()];
        ByteBuffer buffer = ByteBuffer.wrap(data);
        InetSocketAddress address = (InetSocketAddress) channel.receive(buffer);
        int length = buffer.position();
        if (log.isDebugEnabled()) {
            log.debug("Received packet from " + address + " with length " + length);
        }
        callback.receive(endpoint, data, length, new UDPOutTransportInfo(address));
    } catch (IOException ex) {
        endpoint.getMetrics().incrementFaultsReceiving();
        log.error("Error receiving UDP packet", ex);
    }
}

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