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[] argv) throws Exception {
    // Create a read/writeable file channel
    File file = new File("filename");
    FileChannel channel = new RandomAccessFile(file, "rw").getChannel();

    InputStream is = Channels.newInputStream(channel);

    // Close the channel
    is.close();/*from www. j  a v  a  2 s.co  m*/
}

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From source file:MainClass.java

public static void main(String args[]) {
    RandomAccessFile randomAccessFile;
    FileChannel fileChannel;/* ww w.ja v  a 2s .c  om*/
    ByteBuffer byteBuffer;

    try {
        randomAccessFile = new RandomAccessFile("test.txt", "rw");
        fileChannel = randomAccessFile.getChannel();
        byteBuffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, 26);
        for (int i = 0; i < 10; i++)
            byteBuffer.put((byte) ('A' + i));
        fileChannel.close();
        randomAccessFile.close();
    } catch (IOException exc) {
        System.out.println(exc);
        System.exit(1);
    }
}

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From source file:RawDataFromImageFilePDF.java

public static void main(String[] args) {
    Document document = new Document();
    try {//w  w w  .  j av a2 s . c  o  m
        PdfWriter.getInstance(document, new FileOutputStream("RawDataFromImageFilePDF.pdf"));
        document.open();

        RandomAccessFile rf = new RandomAccessFile("logo.png", "r");
        int size = (int) rf.length();
        byte imext[] = new byte[size];
        rf.readFully(imext);
        rf.close();

        Image img1 = Image.getInstance(imext);
        img1.setAbsolutePosition(50, 500);
        document.add(img1);

    } catch (Exception e) {
        System.err.println(e.getMessage());
    }
    document.close();
}

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From source file:RawDataFromImageFileAndManipulationPDF.java

public static void main(String[] args) {
    Document document = new Document();
    try {//from  w  w w  .j  a  v  a 2 s .  com
        PdfWriter.getInstance(document, new FileOutputStream("RawDataFromImageFileAndManipulationPDF.pdf"));
        document.open();

        RandomAccessFile rf = new RandomAccessFile("logo.png", "r");
        int size = (int) rf.length();
        byte imext[] = new byte[size];
        rf.readFully(imext);
        rf.close();

        for (int i = 0; i < imext.length; i++) {
            imext[i] = (byte) (imext[i] + 3);
        }

        Image img1 = Image.getInstance(100, 100, 3, 8, imext);
        img1.setAbsolutePosition(200, 200);
        document.add(img1);

    } catch (Exception e) {
        System.err.println(e.getMessage());
    }
    document.close();
}

---

From source file:Main.java

static public void main(String args[]) throws Exception {
    File infile = new File("inFilename");
    File outfile = new File("outFilename");

    RandomAccessFile inraf = new RandomAccessFile(infile, "r");
    RandomAccessFile outraf = new RandomAccessFile(outfile, "rw");

    FileChannel finc = inraf.getChannel();
    FileChannel foutc = outraf.getChannel();

    MappedByteBuffer inmbb = finc.map(FileChannel.MapMode.READ_ONLY, 0, (int) infile.length());

    Charset inCharset = Charset.forName("UTF8");
    Charset outCharset = Charset.forName("UTF16");

    CharsetDecoder inDecoder = inCharset.newDecoder();
    CharsetEncoder outEncoder = outCharset.newEncoder();

    CharBuffer cb = inDecoder.decode(inmbb);
    ByteBuffer outbb = outEncoder.encode(cb);

    foutc.write(outbb);/*from w  w  w.  jav a  2 s. co m*/

    inraf.close();
    outraf.close();
}

---

From source file:Main.java

public static void main(String[] args) throws Exception {
    fc = new RandomAccessFile("test.dat", "rw").getChannel();
    MappedByteBuffer out = fc.map(FileChannel.MapMode.READ_WRITE, 0, LENGTH);
    for (int i = 0; i < LENGTH; i++)
        out.put((byte) 'x');
    new LockAndModify(out, 0, 0 + LENGTH / 3);
    new LockAndModify(out, LENGTH / 2, LENGTH / 2 + LENGTH / 4);
}

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From source file:MainClass.java

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

    if (args.length < 2) {
        System.err.println("Usage: java MainClass inFile1 inFile2... outFile");
        return;/*www . j a  v a 2  s. c  om*/
    }

    ByteBuffer[] buffers = new ByteBuffer[args.length - 1];
    for (int i = 0; i < args.length - 1; i++) {
        RandomAccessFile raf = new RandomAccessFile(args[i], "r");
        FileChannel channel = raf.getChannel();
        buffers[i] = channel.map(FileChannel.MapMode.READ_ONLY, 0, raf.length());
    }

    FileOutputStream outFile = new FileOutputStream(args[args.length - 1]);
    FileChannel out = outFile.getChannel();
    out.write(buffers);
    out.close();
}

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From source file:CreateEmployeeFile.java

public static void main(String[] args) throws Exception {
    String[] fnames = { "A", "B", "C" };

    String[] lnames = { "a", "b", "c" };

    String[] addresses = { "Box 100", "55 Street", "6 Lane" };

    byte[] ages = { 46, 59, 32 };

    double[] salaries = { 5.0, 6.0, 3.0 };

    RandomAccessFile raf = new RandomAccessFile("employee.dat", "rw");

    EmployeeRecord er = new EmployeeRecord();

    for (int i = 0; i < fnames.length; i++) {
        er.setFirstName(fnames[i]);//from www . ja v a 2  s  .  c o  m
        er.setLastName(lnames[i]);
        er.setAddress(addresses[i]);
        er.setAge(ages[i]);
        er.setSalary(salaries[i]);
        er.write(raf);
    }
    raf = new RandomAccessFile("employee.dat", "rw");

    er = new EmployeeRecord();

    int numRecords = (int) raf.length() / er.size();

    for (int i = 0; i < numRecords; i++) {
        er.read(raf);

        System.out.print(er.getFirstName() + " ");
        System.out.print(er.getLastName() + " ");
        System.out.print(er.getAddress() + " ");
        System.out.print(er.getAge() + " ");
        System.out.println(er.getSalary());
    }
    raf.seek(0);
    for (int i = 0; i < numRecords; i++) {
        er.read(raf);
        if (er.getAge() >= 55) {
            er.setSalary(0.0);
            raf.seek(raf.getFilePointer() - er.size());
            er.write(raf);
            raf.seek(raf.getFilePointer() - er.size());
            er.read(raf);
        }
        System.out.print(er.getFirstName() + " ");
        System.out.print(er.getLastName() + " ");
        System.out.print(er.getAddress() + " ");
        System.out.print(er.getAge() + " ");
        System.out.println(er.getSalary());
    }

}

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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   www  . j  av  a2  s .  c  o m*/
    // 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());
}

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From source file:Main.java

public static void main(String[] args) throws Exception {
    ZipInputStream zipinputstream = new ZipInputStream(new FileInputStream("filename"));
    ZipEntry zipentry = zipinputstream.getNextEntry();
    while (zipentry != null) {
        String entryName = zipentry.getName();
        File newFile = new File(entryName);
        String directory = newFile.getParent();
        if (directory == null) {
            if (newFile.isDirectory())
                break;
        }/*from w ww . j a v  a2s  . com*/
        RandomAccessFile rf = new RandomAccessFile(entryName, "r");
        String line;
        if ((line = rf.readLine()) != null) {
            System.out.println(line);
        }
        rf.close();
        zipinputstream.closeEntry();
        zipentry = zipinputstream.getNextEntry();
    }
    zipinputstream.close();
}

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