Example usage for java.io RandomAccessFile RandomAccessFile

Introduction

In this page you can find the example usage for java.io RandomAccessFile RandomAccessFile.

Prototype

public RandomAccessFile(File file, String mode) throws FileNotFoundException

Source Link

Document

Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument.

Usage

From source file:Main.java

public static void main(String[] args) {
    try {//from  w  ww .  j a va2  s  .  c  om
        byte[] b1 = { 1, 2, 3 };
        byte[] b2 = { 1, 2, 3, 4, 5, 6, 7, 8 };

        RandomAccessFile raf = new RandomAccessFile("c:/test.txt", "rw");

        // write something in the file
        raf.writeUTF("java2s.com Hello World");

        // set the file pointer at 0 position
        raf.seek(0);

        // read the first 8 bytes and print the number of bytes read
        System.out.println(raf.read(b1));

        // set the file pointer at 0 position
        raf.seek(0);

        // read the first 8 bytes and print the number of bytes read
        System.out.println(raf.read(b2));
        raf.close();
    } catch (IOException ex) {
        ex.printStackTrace();
    }

}

From source file:Main.java

public static void main(String[] args) {
    try {/* www . j a v  a 2s.c  o  m*/
        byte[] b1 = { 1, 2, 3 };
        byte[] b2 = { 1, 2, 3, 4, 5, 6, 7, 8 };

        RandomAccessFile raf = new RandomAccessFile("c:/test.txt", "rw");

        // write something in the file
        raf.writeUTF("Hello World from java2s.com");

        // set the file pointer at 0 position
        raf.seek(0);

        // read 2 bytes, starting from 1
        System.out.println(raf.read(b1, 1, 2));

        // set the file pointer at 0 position
        raf.seek(0);

        // read 3 bytes, starting from 4rth
        System.out.println(raf.read(b2, 4, 3));
        raf.close();
    } catch (IOException ex) {
        ex.printStackTrace();
    }

}

From source file:MainClass.java

public static void main(String[] args) throws IOException {
    FileChannel fc = new RandomAccessFile(new File("temp.tmp"), "rw").getChannel();
    IntBuffer ib = fc.map(FileChannel.MapMode.READ_WRITE, 0, fc.size()).asIntBuffer();
    ib.put(0);/*from  w w w .  j  a v a2s.c o  m*/
    for (int i = 1; i < 10; i++)
        ib.put(ib.get(i - 1));
    fc.close();

}

From source file:Main.java

public static void main(String[] args) throws Exception {
    RandomAccessFile raf = new RandomAccessFile("test.txt", "rw");
    FileChannel fileChannel = raf.getChannel();
    FileLock lock = null;/*  w  w w . ja va 2  s  .  c o m*/
    try {
        lock = fileChannel.lock(0, 10, true);

    } catch (IOException e) {
        // Handle the exception
    } finally {
        if (lock != null) {
            try {
                lock.release();
            } catch (IOException e) {
                // Handle the exception
            }
        }
    }

}

From source file:MainClass.java

public static void main(String[] args) throws Exception {
    MappedByteBuffer out = new RandomAccessFile("test.dat", "rw").getChannel()
            .map(FileChannel.MapMode.READ_WRITE, 0, length);
    for (int i = 0; i < length; i++)
        out.put((byte) 'x');
    System.out.println("Finished writing");
    for (int i = length / 2; i < length / 2 + 6; i++)
        System.out.print((char) out.get(i));
}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    File file = new File("filename");

    FileChannel roChannel = new RandomAccessFile(file, "r").getChannel();
    ByteBuffer roBuf = roChannel.map(FileChannel.MapMode.READ_ONLY, 0, (int) roChannel.size());
}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    String filename = "test.dat";

    RandomAccessFile raf1 = new RandomAccessFile(filename, "rw");
    FileChannel fc1 = raf1.getChannel();

    RandomAccessFile raf2 = new RandomAccessFile(filename, "rw");
    FileChannel fc2 = raf2.getChannel();

    System.out.println("Grabbing first lock");
    FileLock lock1 = fc1.lock(0L, Integer.MAX_VALUE, false);

    System.out.println("Grabbing second lock");
    FileLock lock2 = fc2.lock(5, 10, false);

    System.out.println("Exiting");
}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    File file = new File("filename");
    FileChannel channel = new RandomAccessFile(file, "rw").getChannel();
    MappedByteBuffer buf = channel.map(FileChannel.MapMode.READ_WRITE, 0, (int) channel.size());

    buf.put(0, (byte) 0xFF);

    buf.force();//from  ww w . jav  a2s. c o  m

    channel.close();
}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    File file = new File("filename");
    FileChannel roChannel = new RandomAccessFile(file, "r").getChannel();
    ByteBuffer readonlybuffer = roChannel.map(FileChannel.MapMode.READ_ONLY, 0, (int) roChannel.size());

    FileChannel rwChannel = new RandomAccessFile(file, "rw").getChannel();
    ByteBuffer writeonlybuffer = rwChannel.map(FileChannel.MapMode.READ_WRITE, 0, (int) rwChannel.size());

    // Create a private (copy-on-write) memory-mapped file.
    FileChannel pvChannel = new RandomAccessFile(file, "rw").getChannel();

    ByteBuffer privatebuffer = roChannel.map(FileChannel.MapMode.READ_WRITE, 0, (int) rwChannel.size());

}

From source file:Main.java

public static void main(String[] argv) throws Exception {
    File file = new File("filename");
    FileChannel channel = new RandomAccessFile(file, "rw").getChannel();

    FileLock lock = channel.lock();

    lock = channel.tryLock();/* w w w . j av  a 2s  .com*/

    lock.release();

    channel.close();
}