Reading bytes from FileChannel...

[Lionel Kingsley]

Hi,

I want to read file content into bytebuffer and then decode ByteBuffer bb to CharBuffer. At last i want to close the FileChannel and delete the inputFile. I tried the following program.

FileChannel fc = new RandomAccessFile(inputFile, "r").getChannel();
ByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
CharBuffer cb = Charset.forName("ISO-8859-1").decode(bb);

The above program works fine. FileChannel.map() method directly maps to the file and get the MappedByteBuffer. But it has a drawback of not releasing the file even though the FileChannel gets closed. It has been reported as a bug in Sun java bug database.

I came to know that if i use FileChannel.read() method to resolve the problem i got. So i tried the following program.

FileChannel fc = new RandomAccessFile(inputFile, "r").getChannel();
ByteBuffer bb = ByteBuffer.allocate((int)fc.size());
fc.read(bb, 0);
 
CharsetDecoder cd = Charset.forName("ISO-8859-1").newDecoder();
CharBuffer cb = CharBuffer.allocate((int)fc.size());
cb = cd.decode(bb);

I wonder it is not decoding the bytebuffer to charbuffer.

Please help me to resolve this problem.

Thank you.

[Nitesh Kant]

If you do not really require a non blocking IO then instead of using channels you can use any implementations of java.io.Reader. These are convenience classes just for reading character streams.