Example usage for java.nio.channels FileChannel size

Introduction

In this page you can find the example usage for java.nio.channels FileChannel size.

Prototype

public abstract long size() throws IOException;

Source Link

Document

Returns the current size of this channel's file.

Usage

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;//ww  w . ja va 2s .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:MainClass.java

public static void main(String[] args) {
    long[] primes = new long[] { 1, 2, 3, 5, 7 };
    File aFile = new File("C:/test/primes.txt");
    FileOutputStream outputFile = null;
    try {/*from  w ww.  ja  v a2  s .c  o  m*/
        outputFile = new FileOutputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    }
    FileChannel file = outputFile.getChannel();
    final int BUFFERSIZE = 100;
    ByteBuffer buf = ByteBuffer.allocate(BUFFERSIZE);
    DoubleBuffer doubleBuf = buf.asDoubleBuffer();
    buf.position(8);
    CharBuffer charBuf = buf.asCharBuffer();
    for (long prime : primes) {
        String primeStr = "prime = " + prime;
        doubleBuf.put(0, (double) primeStr.length());
        charBuf.put(primeStr);
        buf.position(2 * charBuf.position() + 8);
        LongBuffer longBuf = buf.asLongBuffer();
        longBuf.put(prime);
        buf.position(buf.position() + 8);
        buf.flip();
        try {
            file.write(buf);
        } catch (IOException e) {
            e.printStackTrace(System.err);
        }
        buf.clear();
        doubleBuf.clear();
        charBuf.clear();
    }
    try {
        System.out.println("File written is " + file.size() + "bytes.");
        outputFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
}

From source file:Main.java

public static byte[] readFileToMemory(String file) throws IOException {
    FileInputStream fis = new FileInputStream(file);
    FileChannel fileChannel = fis.getChannel();
    long size = fileChannel.size();
    MappedByteBuffer mappedByteBuffer = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, size);
    byte[] data = new byte[(int) size];
    mappedByteBuffer.get(data, 0, (int) size);
    fileChannel.close();/*  w ww . ja  v a2s . co  m*/
    fis.close();
    return data;
    //      return readFileToMemory(new File(file));
}

From source file:Main.java

public static void copyFileFast(FileInputStream is, FileOutputStream os) throws IOException {
    FileChannel in = is.getChannel();
    FileChannel out = os.getChannel();
    in.transferTo(0, in.size(), out);
}

From source file:z.tool.util.FileUtil.java

/**
 * ?//w  w w .  jav  a2 s  . co  m
 */
public static void copy(FileInputStream fis, FileOutputStream fos) throws IOException {
    FileChannel channel = fis.getChannel();
    channel.transferTo(0, channel.size(), fos.getChannel());
}

From source file:Main.java

public static String readFile(String path) throws IOException {
    FileInputStream stream = new FileInputStream(new File(path));
    String str = null;//from  ww w  . j a  v a  2 s  .  co  m
    try {
        FileChannel fc = stream.getChannel();
        MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
        /* Instead of using default, pass in a decoder. */
        str = Charset.defaultCharset().decode(bb).toString();
    } finally {
        stream.close();
    }
    return str;
}

From source file:Main.java

public static CharSequence fromFile(String filename) throws IOException {
    FileInputStream fis = new FileInputStream(filename);
    FileChannel fc = fis.getChannel();

    // Create a read-only CharBuffer on the file
    ByteBuffer bbuf = fc.map(FileChannel.MapMode.READ_ONLY, 0, (int) fc.size());
    CharBuffer cbuf = Charset.forName("8859_1").newDecoder().decode(bbuf);
    return cbuf;//from   ww  w  . j  a v a  2 s  . c  o  m
}

From source file:Main.java

public static void copy(File src, File dst) throws IOException {
    FileInputStream inStream = new FileInputStream(src);
    FileOutputStream outStream = new FileOutputStream(dst);
    FileChannel inChannel = inStream.getChannel();
    FileChannel outChannel = outStream.getChannel();
    inChannel.transferTo(0, inChannel.size(), outChannel);
    inStream.close();// w  w w.  ja v  a 2  s . c  o m
    outStream.close();
}

From source file:Main.java

static public String getFileContent(String filename) throws IOException {
    File file = new File(filename);
    FileInputStream stream = new FileInputStream(file);
    try {/*from  www  .  j  a v a 2  s  .c o  m*/
        FileChannel fc = stream.getChannel();
        MappedByteBuffer mbb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());

        return Charset.defaultCharset().decode(mbb).toString();
    } finally {
        stream.close();
    }
}

From source file:Main.java

public static void copyFile(File src, File dest) throws IOException {
    FileOutputStream fileOut = null;
    FileInputStream fileIn = null;
    try {//from www  .j  a va  2 s.com
        fileOut = new FileOutputStream(dest);
        fileIn = new FileInputStream(src);
        FileChannel inChannel = fileIn.getChannel();
        FileChannel outChannel = fileOut.getChannel();
        inChannel.transferTo(0, inChannel.size(), outChannel);
    } finally {
        if (fileIn != null) {
            fileIn.close();
        }
        if (fileOut != null) {
            fileOut.close();
        }
    }
}