Example usage for java.nio ByteBuffer allocate

List of usage examples for java.nio ByteBuffer allocate

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Introduction

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

Prototype

public static ByteBuffer allocate(int capacity)

Source Link

Document

Creates a byte buffer based on a newly allocated byte array.

Usage

From source file:Main.java

public static void main(String[] args) throws Exception {
    AsynchronousSocketChannel channel = AsynchronousSocketChannel.open();
    SocketAddress serverAddr = new InetSocketAddress("localhost", 8989);
    Future<Void> result = channel.connect(serverAddr);
    result.get();/*from  www  . j  a  v  a  2s  .  c o m*/
    System.out.println("Connected");
    Attachment attach = new Attachment();
    attach.channel = channel;
    attach.buffer = ByteBuffer.allocate(2048);
    attach.isRead = false;
    attach.mainThread = Thread.currentThread();

    Charset cs = Charset.forName("UTF-8");
    String msg = "Hello";
    byte[] data = msg.getBytes(cs);
    attach.buffer.put(data);
    attach.buffer.flip();

    ReadWriteHandler readWriteHandler = new ReadWriteHandler();
    channel.write(attach.buffer, attach, readWriteHandler);
    attach.mainThread.join();
}

From source file:MainClass.java

public static void main(String[] args) {
    String phrase = new String("text \n");
    String dirname = "C:/test";
    String filename = "charData.txt";
    File dir = new File(dirname);
    File aFile = new File(dir, filename);
    FileOutputStream outputFile = null;
    try {/*from w ww  .j a  v  a  2s .  c o  m*/
        outputFile = new FileOutputStream(aFile, true);
        System.out.println("File stream created successfully.");
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    }
    FileChannel outChannel = outputFile.getChannel();
    ByteBuffer buf = ByteBuffer.allocate(1024);
    System.out.println("New buffer:           position = " + buf.position() + "\tLimit = " + buf.limit()
            + "\tcapacity = " + buf.capacity());
    for (char ch : phrase.toCharArray()) {
        buf.putChar(ch);
    }
    System.out.println("Buffer after loading: position = " + buf.position() + "\tLimit = " + buf.limit()
            + "\tcapacity = " + buf.capacity());
    buf.flip();
    System.out.println("Buffer after flip:   position = " + buf.position() + "\tLimit = " + buf.limit()
            + "\tcapacity = " + buf.capacity());
    try {
        outChannel.write(buf);
        outputFile.close();
        System.out.println("Buffer contents written to file.");
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
}

From source file:MainClass.java

public static void main(String[] args) {
    String[] phrases = { "A", "B 1", "C 1.3" };
    String dirname = "C:/test";
    String filename = "Phrases.txt";
    File dir = new File(dirname);
    File aFile = new File(dir, filename);
    FileOutputStream outputFile = null;
    try {// ww  w.java2s  . co  m
        outputFile = new FileOutputStream(aFile, true);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    }
    FileChannel outChannel = outputFile.getChannel();
    ByteBuffer buf = ByteBuffer.allocate(1024);
    System.out.println(buf.position());
    System.out.println(buf.limit());
    System.out.println(buf.capacity());
    CharBuffer charBuf = buf.asCharBuffer();
    System.out.println(charBuf.position());
    System.out.println(charBuf.limit());
    System.out.println(charBuf.capacity());
    Formatter formatter = new Formatter(charBuf);
    int number = 0;
    for (String phrase : phrases) {
        formatter.format("%n %s", ++number, phrase);
        System.out.println(charBuf.position());
        System.out.println(charBuf.limit());
        System.out.println(charBuf.capacity());
        charBuf.flip();
        System.out.println(charBuf.position());
        System.out.println(charBuf.limit());
        System.out.println(charBuf.length());
        buf.limit(2 * charBuf.length()); // Set byte buffer limit
        System.out.println(buf.position());
        System.out.println(buf.limit());
        System.out.println(buf.remaining());
        try {
            outChannel.write(buf);
            buf.clear();
            charBuf.clear();
        } catch (IOException e) {
            e.printStackTrace(System.err);
        }
    }
    try {
        outputFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
}

From source file:MainClass.java

public static void main(String[] args) {
    int count = 100;

    long[] numbers = new long[count];

    for (int i = 0; i < numbers.length; i++) {
        numbers[i] = i;//from www  .j  a va  2 s .c o  m

    }
    File aFile = new File("data.bin");
    FileOutputStream outputFile = null;
    try {
        outputFile = new FileOutputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }
    FileChannel file = outputFile.getChannel();
    final int BUFFERSIZE = 100;
    ByteBuffer buf = ByteBuffer.allocate(BUFFERSIZE);
    LongBuffer longBuf = buf.asLongBuffer();

    int numberWritten = 0;

    while (numberWritten < numbers.length) {
        longBuf.put(numbers, numberWritten, min(longBuf.capacity(), numbers.length - numberWritten));
        buf.limit(8 * longBuf.position());
        try {
            file.write(buf);
            numberWritten += longBuf.position();
        } catch (IOException e) {
            e.printStackTrace(System.err);
            System.exit(1);
        }
        longBuf.clear();
        buf.clear();
    }

    try {
        System.out.println("File written is " + file.size() + " bytes.");
        outputFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }
}

From source file:GetChannel.java

public static void main(String[] args) throws Exception {
    // Write a file:
    FileChannel fc = new FileOutputStream("data.txt").getChannel();
    fc.write(ByteBuffer.wrap("Some text ".getBytes()));
    fc.close();/*from w ww.ja  v  a  2s .c  om*/
    // Add to the end of the file:
    fc = new RandomAccessFile("data.txt", "rw").getChannel();
    fc.position(fc.size()); // Move to the end
    fc.write(ByteBuffer.wrap("Some more".getBytes()));
    fc.close();
    // Read the file:
    fc = new FileInputStream("data.txt").getChannel();
    ByteBuffer buff = ByteBuffer.allocate(BSIZE);
    fc.read(buff);
    buff.flip();
    while (buff.hasRemaining())
        System.out.print((char) buff.get());
}

From source file:MainClass.java

public static void main(String[] args) {
    String phrase = new String("www.java2s.com\n");

    File aFile = new File("test.txt");
    FileOutputStream outputFile = null;
    try {/*  w w  w.  j  ava2  s .  co m*/
        outputFile = new FileOutputStream(aFile, true);
        System.out.println("File stream created successfully.");
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    }

    FileChannel outChannel = outputFile.getChannel();

    ByteBuffer buf = ByteBuffer.allocate(1024);
    System.out.println("New buffer:           position = " + buf.position() + "\tLimit = " + buf.limit()
            + "\tcapacity = " + buf.capacity());

    // Load the data into the buffer
    for (char ch : phrase.toCharArray()) {
        buf.putChar(ch);
    }
    System.out.println("Buffer after loading: position = " + buf.position() + "\tLimit = " + buf.limit()
            + "\tcapacity = " + buf.capacity());
    buf.flip();
    System.out.println("Buffer after flip:    position = " + buf.position() + "\tLimit = " + buf.limit()
            + "\tcapacity = " + buf.capacity());

    try {
        outChannel.write(buf);
        outputFile.close();
        System.out.println("Buffer contents written to file.");
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
}

From source file:MainClass.java

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

    URL u = new URL("http://www.java2s.com");
    String host = u.getHost();//from  ww  w  .  ja va 2s.c o m
    int port = 80;
    String file = "/";

    SocketAddress remote = new InetSocketAddress(host, port);
    SocketChannel channel = SocketChannel.open(remote);
    FileOutputStream out = new FileOutputStream("yourfile.htm");
    FileChannel localFile = out.getChannel();

    String request = "GET " + file + " HTTP/1.1\r\n" + "User-Agent: HTTPGrab\r\n" + "Accept: text/*\r\n"
            + "Connection: close\r\n" + "Host: " + host + "\r\n" + "\r\n";

    ByteBuffer header = ByteBuffer.wrap(request.getBytes("US-ASCII"));
    channel.write(header);

    ByteBuffer buffer = ByteBuffer.allocate(8192);
    while (channel.read(buffer) != -1) {
        buffer.flip();
        localFile.write(buffer);
        buffer.clear();
    }

    localFile.close();
    channel.close();
}

From source file:com.moscona.dataSpace.debug.ByteBufferTest.java

public static void main(String[] args) {
    ByteBuffer bytes = ByteBuffer.allocate(40);
    print("after allocation", bytes);
    byte[] byteArray = bytes.array();
    for (int i = 0; i < byteArray.length; i++) {
        byteArray[i] = 1;/*from  www .  ja  v  a  2 s.  c o  m*/
    }
    print("after filling with 1s", bytes);
    IntBuffer ints = bytes.asIntBuffer();
    System.out.println("ints has array: " + ints.hasArray());
    int[] array = ints.array();
    for (int i = 0; i < array.length; i++) {
        array[i] = 100 + i;
    }
    print("after filling ints array", bytes);
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    MembershipKey key = null;//from  w w w. ja  va2  s .  com
    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();
}

From source file:Test.java

public static void main(String args[]) throws Exception {
    ExecutorService pool = new ScheduledThreadPoolExecutor(3);
    AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(Paths.get("data.txt"),
            EnumSet.of(StandardOpenOption.READ), pool);
    CompletionHandler<Integer, ByteBuffer> handler = new CompletionHandler<Integer, ByteBuffer>() {
        public synchronized void completed(Integer result, ByteBuffer attachment) {
            for (int i = 0; i < attachment.limit(); i++) {
                System.out.print((char) attachment.get(i));
            }// w  ww  .ja  va  2s .  c  o m
        }

        public void failed(Throwable e, ByteBuffer attachment) {
        }
    };
    final int bufferCount = 5;
    ByteBuffer buffers[] = new ByteBuffer[bufferCount];
    for (int i = 0; i < bufferCount; i++) {
        buffers[i] = ByteBuffer.allocate(10);
        fileChannel.read(buffers[i], i * 10, buffers[i], handler);
    }
    pool.awaitTermination(1, TimeUnit.SECONDS);
    for (ByteBuffer byteBuffer : buffers) {
        for (int i = 0; i < byteBuffer.limit(); i++) {
            System.out.println((char) byteBuffer.get(i));
        }
    }
}