Trying to upload in chunks

I am trying to accomplish a large file upload on a blackberry. I am succesfully able to upload a file but only if I read the file and upload it 1 byte at a time. For large files I think this is decreasing performance. I want to be able to read and write at something more 128 kb at a time. If i try to initialise my buffer to anything other than 1 then I never get a response back from the server after writing everything.

Any ideas why i can upload using only 1 byte at a time?

z.write(boundaryMessage.toString().getBytes());
DataInputStream fileIn = fc.openDataInputStream();
boolean isCancel = false;

byte[]b = new byte[1];
int num = 0;
int left = buffer;

while((fileIn.read(b)>-1))
{
  num += b.length;
  left = buffer - num * 1;
  Log.info(num + 开发者_如何转开发"WRITTEN");

  if (isCancel == true)
  {
    break;
  }

  z.write(b);
}
z.write(endBoundary.toString().getBytes());

It's a bug in BlackBerry OS that appeared in OS 5.0, and persists in OS 6.0. If you try using a multi-byte read before OS 5, it will work fine. OS5 and later produce the behavior you have described.

You can also get around the problem by creating a secure connection, as the bug doesn't manifest itself for secure sockets, only plain sockets.

Most input streams aren't guaranteed to fill a buffer on every read. (DataInputStream has a special method for this, readFully(), which will throw an EOFException if there aren't enough bytes left in the stream to fill the buffer.) And unless the file is a multiple of the buffer length, no stream will fill the buffer on the final read. So, you need to store the number of bytes read and use it during the write:

while(!isCancel)
{
  int n = fileIn.read(b);
  if (n < 0)
    break;
  num += n;
  Log.info(num + "WRITTEN");
  z.write(b, 0, n);
}

Your loop isn't correct. You should take care of the return value from read. It returns how many bytes that were actually read, and that isn't always the same as the buffer size.

Edit: This is how you usually write loops that does what you want to do:

OutputStream z = null;  //Shouldn't be null
InputStream in = null;  //Shouldn't be null
byte[] buffer = new byte[1024 * 32];
int len = 0;
while ((len = in.read(buffer)) > -1) {
    z.write(buffer, 0, len);
}

Note that you might want to use buffered streams instead of unbuffered streams.