Example usage for java.nio ByteBuffer allocate

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 IOException {
    FileInputStream fis = new FileInputStream("FileChannelExample.java");
    FileChannel fc = fis.getChannel();

    ByteBuffer bb = ByteBuffer.allocate((int) fc.size());

    fc.read(bb);/*from   w  w w  . j  a  va 2  s  . c om*/
    bb.flip();

    String fileContent = new String(bb.array());

    fc.close();
    fc = null;

    System.out.println("fileContent = " + fileContent);
}

From source file:Main.java

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

    ByteBuffer bbuf = ByteBuffer.wrap(new byte[10]);
    boolean isDirect = bbuf.isDirect(); // false

    bbuf = ByteBuffer.allocate(10);
    isDirect = bbuf.isDirect(); // false

    bbuf = ByteBuffer.allocateDirect(10);
    isDirect = bbuf.isDirect(); // true

}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    // Create a ByteBuffer using a byte array
    byte[] bytes = new byte[10];
    ByteBuffer buffer = ByteBuffer.wrap(bytes);

    // Create a non-direct ByteBuffer with a 10 byte capacity
    // The underlying storage is a byte array.
    buffer = ByteBuffer.allocate(10);

    // Create a memory-mapped ByteBuffer with a 10 byte capacity.
    buffer = ByteBuffer.allocateDirect(10);
}

From source file:Test.java

public static void main(String[] args) throws Exception {
    Path file = Paths.get("/usr/a.txt");
    AsynchronousFileChannel channel = AsynchronousFileChannel.open(file);

    ByteBuffer buffer = ByteBuffer.allocate(100_000);
    Future<Integer> result = channel.read(buffer, 0);

    while (!result.isDone()) {
        ProfitCalculator.calculateTax();
    }//from  w w w.  jav a  2s  . c o m
    Integer bytesRead = result.get();
    System.out.println("Bytes read [" + bytesRead + "]");
}

From source file:IntBufferDemo.java

public static void main(String[] args) {
    ByteBuffer bb = ByteBuffer.allocate(BSIZE);
    IntBuffer ib = bb.asIntBuffer();
    // Store an array of int:
    ib.put(new int[] { 11, 42, 47, 99, 143, 811, 1016 });
    // Absolute location read and write:
    System.out.println(ib.get(3));
    ib.put(3, 1811);/*from  w  ww. j  a v  a 2  s  .co  m*/
    ib.rewind();
    while (ib.hasRemaining()) {
        int i = ib.get();
        if (i == 0)
            break; // Else we'll get the entire buffer
        System.out.println(i);
    }

}

From source file:Main.java

public static void main(String[] args) throws Exception {
    File aFile = new File("main.java");
    FileInputStream inFile = new FileInputStream(aFile);
    FileChannel inChannel = inFile.getChannel();
    ByteBuffer lengthBuf = ByteBuffer.allocate(8);
    while (true) {
        if (inChannel.read(lengthBuf) == -1) {
            break;
        }//  w w  w  .j a v a2  s. com
        lengthBuf.flip();
        int strLength = (int) lengthBuf.getDouble();
        ByteBuffer buf = ByteBuffer.allocate(2 * strLength + 8);
        if (inChannel.read(buf) == -1) {
            break;
        }
        buf.flip();
        byte[] strChars = new byte[2 * strLength];
        buf.get(strChars);
        System.out.println(strLength);
        System.out.println(ByteBuffer.wrap(strChars).asCharBuffer());
        System.out.println(buf.getLong());
        lengthBuf.clear();
    }
    inFile.close();
}

From source file:GetData.java

public static void main(String[] args) {
    ByteBuffer bb = ByteBuffer.allocate(BSIZE);
    // Allocation automatically zeroes the ByteBuffer:
    int i = 0;/* w w  w.  j  a  v a  2s  .  com*/
    while (i++ < bb.limit())
        if (bb.get() != 0)
            System.out.println("nonzero");
    System.out.println("i = " + i);
    bb.rewind();
    // Store and read a char array:
    bb.asCharBuffer().put("Howdy!");
    char c;
    while ((c = bb.getChar()) != 0)
        System.out.print(c + " ");
    System.out.println();
    bb.rewind();
    // Store and read a short:
    bb.asShortBuffer().put((short) 471142);
    System.out.println(bb.getShort());
    bb.rewind();
    // Store and read an int:
    bb.asIntBuffer().put(99471142);
    System.out.println(bb.getInt());
    bb.rewind();
    // Store and read a long:
    bb.asLongBuffer().put(99471142);
    System.out.println(bb.getLong());
    bb.rewind();
    // Store and read a float:
    bb.asFloatBuffer().put(99471142);
    System.out.println(bb.getFloat());
    bb.rewind();
    // Store and read a double:
    bb.asDoubleBuffer().put(99471142);
    System.out.println(bb.getDouble());
    bb.rewind();

}

From source file:MainClass.java

public static void main(String[] args) throws Exception {
    File aFile = new File("charData.xml");
    FileInputStream inFile = null;

    inFile = new FileInputStream(aFile);

    FileChannel inChannel = inFile.getChannel();
    ByteBuffer buf = ByteBuffer.allocate(48);

    while (inChannel.read(buf) != -1) {
        System.out.println("String read: " + ((ByteBuffer) (buf.flip())).asCharBuffer().get(0));
        buf.clear();/*from  w w  w.  j a  va  2 s  . c  o m*/
    }
    inFile.close();
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    FileChannel in = new FileInputStream("source.txt").getChannel(),
            out = new FileOutputStream("target.txt").getChannel();
    ByteBuffer buffer = ByteBuffer.allocate(BSIZE);
    while (in.read(buffer) != -1) {
        buffer.flip();/*from w  w  w  .j  av a  2s .  c  om*/
        out.write(buffer);
        buffer.clear();
    }
}

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);
        }/*from ww w .j a v  a 2  s  .  c  o  m*/
        buf.clear();
    }
    inFile.close();
}