Java NIO - reading large amount of data

Question

Hi,
I have diffuculties of reading large amount of data with SocketChannel (using directAllocated buffer & allocated one). Files greater than 300KB are cut even though I tried write the data into FileChannel.
My Code:
ByteBuffer directBlockBuffer = ByteBuffer.allocateDirect(150000);
buffer = ByteBuffer.allocate(6000000);
out = new     FOS("d:\\msgData.tmp");
fc=out.getFOS().getChannel(); // FileChannel               
int fileLength = (int)fc.size();
while (clientChannel.read(directBlockBuffer)>0)
{                              directBlockBuffer.flip()                         buffer.put(directBlockBuffer);
     directBlockBuffer.compact();
//close data file
                                   buffer.flip();
                                   fc.write(buffer);
                                   fc.close();
FOS.close();
// end of code
Any ideas?
Thanks
AST

Answer 1

I don't understand how the "write" result will help read the whole data.
Anyway, I changed the code so the SocketChannel will read in smaller chunks (~8KB) & the FileChannel writes in every read
but the data stream is cut again (to ~5KB no matter what size of file I send).
In the updated code when try to compare socketChannel.read to -1 I got endless loop.
I'm basically trying to write POP3/SMTP server program, this part of code handles attachment that is received by the SocketChannel in one unit (i.e 1+ MB of data, the other SMTP commands/lines are no more than 27 chars and simple to handle).
Therefore I need to be ready to accept large amount of data to the buffer & write it to filechannel. (In the POP3 thread I'm using MappedByteBuffer successfully).
Updated code:
ByteBuffer directBlockBuffer = ByteBuffer.allocateDirect(8192);
while (clientChannel.read   (directBlockBuffer>0&&directBlockBuffer.hasRemaining))
          directBlockBuffer.flip();
          fc.write(directBlockBuffer);
          directBlockBuffer.clear();
     }I think based on API my code is logical (and good for small files) but what about handling bigger files (up to 5MB)?
Thanks,
AST