Example usage for java.nio ByteBuffer clear

List of usage examples for java.nio ByteBuffer clear

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Introduction

In this page you can find the example usage for java.nio ByteBuffer clear.

Prototype

public final Buffer clear()

Source Link

Document

Clears this buffer.

Usage

From source file:Test.java

public static void main(String[] args) throws IOException {
    Path path = Paths.get("/users.txt");

    try (SeekableByteChannel sbc = Files.newByteChannel(path)) {
        ByteBuffer buffer = ByteBuffer.allocate(1024);

        sbc.position(4);// w w w .ja v a  2  s.c om
        sbc.read(buffer);
        for (int i = 0; i < 5; i++) {
            System.out.print((char) buffer.get(i));
        }

        buffer.clear();
        sbc.position(0);
        sbc.read(buffer);
        for (int i = 0; i < 4; i++) {
            System.out.print((char) buffer.get(i));
        }

    }
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    String source = "s.txt";
    String destination = "d.txt";

    FileInputStream fis = new FileInputStream(source);
    FileOutputStream fos = new FileOutputStream(destination);

    FileChannel fci = fis.getChannel();
    FileChannel fco = fos.getChannel();

    ByteBuffer buffer = ByteBuffer.allocate(1024);

    while (true) {
        int read = fci.read(buffer);

        if (read == -1)
            break;
        buffer.flip();//from  www . j  av a 2  s .c  o m
        fco.write(buffer);
        buffer.clear();
    }
}

From source file:Test.java

public static void main(String[] args) throws IOException {
    Path path = Paths.get("/users.txt");

    try (SeekableByteChannel sbc = Files.newByteChannel(path)) {
        ByteBuffer buffer = ByteBuffer.allocate(1024);

        sbc.position(4);//from www  .j  a  v a 2  s  . co m
        sbc.read(buffer);
        for (int i = 0; i < 5; i++) {
            System.out.print((char) buffer.get(i));
        }

        buffer.clear();
        sbc.position(0);
        sbc.read(buffer);
        for (int i = 0; i < 4; i++) {
            System.out.print((char) buffer.get(i));
        }
        sbc.position(0);
        buffer = ByteBuffer.allocate(1024);
        String encoding = System.getProperty("file.encoding");
        int numberOfBytesRead = sbc.read(buffer);
        System.out.println("Number of bytes read: " + numberOfBytesRead);
        while (numberOfBytesRead > 0) {
            buffer.rewind();
            System.out.print("[" + Charset.forName(encoding).decode(buffer) + "]");
            buffer.flip();
            numberOfBytesRead = sbc.read(buffer);
            System.out.println("\nNumber of bytes read: " + numberOfBytesRead);
        }

    }

}

From source file:MainClass.java

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

    DatagramChannel channel = DatagramChannel.open();
    SocketAddress address = new InetSocketAddress(0);
    DatagramSocket socket = channel.socket();
    socket.bind(address);//from  w  ww  . ja v  a2  s  .  co m

    SocketAddress server = new InetSocketAddress("time-a.nist.gov", 37);
    channel.connect(server);

    ByteBuffer buffer = ByteBuffer.allocate(8);
    buffer.order(ByteOrder.BIG_ENDIAN);
    // send a byte of data to the server
    buffer.put((byte) 0);
    buffer.flip();
    channel.write(buffer);

    // get the buffer ready to receive data
    buffer.clear();
    // fill the first four bytes with zeros
    buffer.putInt(0);
    channel.read(buffer);
    buffer.flip();

    // convert seconds since 1900 to a java.util.Date
    long secondsSince1900 = buffer.getLong();
    long differenceBetweenEpochs = 2208988800L;
    long secondsSince1970 = secondsSince1900 - differenceBetweenEpochs;
    long msSince1970 = secondsSince1970 * 1000;
    Date time = new Date(msSince1970);

    System.out.println(time);
}

From source file:Main.java

public static void main(String[] args) {
    File inputFile = new File("test1.txt");
    if (!inputFile.exists()) {
        System.out.println("The input file " + inputFile.getAbsolutePath() + "  does  not  exist.");
        System.out.println("Aborted the   file reading process.");
        return;//w ww.  j  a v  a2s.co m
    }
    try (FileChannel fileChannel = new FileInputStream(inputFile).getChannel()) {
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        while (fileChannel.read(buffer) > 0) {
            buffer.flip();
            while (buffer.hasRemaining()) {
                byte b = buffer.get();
                System.out.print((char) b);
            }
            buffer.clear();
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    File aFile = new File("C:/test.bin");
    FileInputStream inFile = new FileInputStream(aFile);
    FileChannel inChannel = inFile.getChannel();
    final int PRIMECOUNT = 6;
    ByteBuffer buf = ByteBuffer.allocate(8 * PRIMECOUNT);
    long[] primes = new long[PRIMECOUNT];
    while (inChannel.read(buf) != -1) {
        ((ByteBuffer) (buf.flip())).asLongBuffer().get(primes);
        for (long prime : primes) {
            System.out.printf("%10d", prime);
        }// w w w .ja  va2  s .com
        buf.clear();
    }
    inFile.close();
}

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);//from w w w  . j a v a2  s  .  co m
    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();

}

From source file:MainClass.java

public static void main(String[] args) {
    File aFile = new File("C:/test.bin");
    FileInputStream inFile = null;
    try {//  ww w.j  a v a2 s  . c  om
        inFile = new FileInputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    }
    FileChannel inChannel = inFile.getChannel();
    final int PRIMECOUNT = 6;
    ByteBuffer buf = ByteBuffer.allocate(8 * PRIMECOUNT);
    long[] primes = new long[PRIMECOUNT];
    try {
        while (inChannel.read(buf) != -1) {
            ((ByteBuffer) (buf.flip())).asLongBuffer().get(primes);
            for (long prime : primes) {
                System.out.printf("%10d", prime);
            }
            buf.clear();
        }
        inFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
}

From source file:MainClass.java

public static void main(String[] args) {
    File aFile = new File("file.dat");
    FileInputStream inFile = null;

    try {/*  www .j a v  a 2 s. co m*/
        inFile = new FileInputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
        System.exit(0);
    }
    FileChannel inChannel = inFile.getChannel();
    final int COUNT = 6;
    ByteBuffer buf = ByteBuffer.allocate(8 * COUNT);
    long[] data = new long[COUNT];
    try {
        while (inChannel.read(buf) != -1) {
            ((ByteBuffer) (buf.flip())).asLongBuffer().get(data);
            System.out.println();
            for (long prime : data)
                System.out.printf("%10d", prime);
            buf.clear();
        }
        System.out.println("\nEOF reached.");
        inFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }
}

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);/*from   w  ww  .  j  ava  2  s  . co  m*/
    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);
        }
    }
}