Java File Read via ByteBuffer readData(String fileName, int size)

Description

read Data

License

Open Source License

Declaration

public final static byte[] readData(String fileName, int size)
            throws IOException 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileChannel.MapMode;

public class Main {
    public final static byte[] readData(String fileName, int size)
            throws IOException {

        final RandomAccessFile fis = new RandomAccessFile(fileName, "r");
        final FileChannel fc = fis.getChannel();
        if (size < 0) {
            size = (int) fc.size();
        }//from   w  w  w.  j  av  a  2  s. c om
        MappedByteBuffer buf = fc.map(MapMode.READ_ONLY, 0, size);
        final byte[] bytes = new byte[size];
        buf.get(bytes);
        fc.force(true);

        fis.close();
        closeDirectBuffer(buf);

        return bytes;
    }

    @SuppressWarnings("restriction")
    public static void closeDirectBuffer(ByteBuffer cb) {
        if (!cb.isDirect())
            return;
        try {
            ((sun.nio.ch.DirectBuffer) cb).cleaner().clean();
        } catch (Exception ex) {
        }
        cb = null;
    }
}

Related

1. readBytes(String file)
2. readCode(byte[] message)
3. readColumnarKeyBlockDataForNoDictionaryCols(byte[] columnarKeyBlockData)
4. readContent(File file)
5. readContentsNIO(FileInputStream input, String encoding, boolean decodeNIO)
6. readDelimitedFromInputStream(InputStream inputStream)
7. readDouble(BufferedReader br, double[] buf)
8. readDouble(byte[] src, int pointer)
9. readDouble(FileChannel fileChannel, ByteOrder byteOrder)