How to save a Java FloatBuffer (or any Buffer) to a file

I have a FloatBuffer of known size and just want to dump the data to a file (in binary) for inspection outside my app. What's the easiest way to do this?

From stackoverflow

• UPDATE FOR BINARY OUTPUT:

  // There are dependencies on how you create your floatbuffer for this to work
  // I suggest starting with a byte buffer and using asFloatBuffer() when
  // you need it as floats.
  // ByteBuffer b = ByteBuffer.allocate(somesize);
  // FloatBuffer fb = b.asFloatBuffer();
  // There will also be endiance issues when you write binary since
  // java is big-endian. You can adjust this with Buffer.order(...)
  // b.order(ByteOrder.LITTLE_ENDIAN)
  // If you're using a hex-editor you'll probably want little endian output
  // since most consumer machines (unless you've got a sparc / old mac) are little
  
  
  FileOutputStream fos = new FileOutputStream("some_binary_output_file_name");
  FileChannel channel = fos.getChannel();
  
  channel.write(byteBufferBackingYourFloatBuffer);
  
  fos.close();
  

  TEXT OUTPUT: Since you want this to be viewable I assume you want a text file. You'll want to use a PrintStream.

  // Try-catch omitted for simplicity
  
  PrintStream ps = new PrintStream("some_output_file.txt");
  for(int i = 0; i < yourFloatBuffer.capacity(); i++)
  {
     // put each float on one line
     // use printf to get fancy (decimal places, etc)
     ps.println(yourFloagBuffer.get(i));
  }
  
  ps.close();
  

  Didn't have time to post a full raw/binary (non-text) version of this. If you want to do that use a FileOutputStream, get the FileChannel, and directly write the FloatBuffer (since it's a ByteBuffer)

  jblocksom : Thanks, although actually I did want to write it all out in binary. Sorry to not be specific about that, I'll update the question.

• This iterates through the array backed by your buffer and outputs each float. Just replace the text file and floatBuffer with your own parameters.

  PrintStream out = new PrintStream("target.txt");
  for(float f : floatBuffer.array()){
    out.println(f);
  }
  out.close();
  

• Asusming you want the data as binary:

  Start with a ByteBuffer. Call asFloatBuffer to get your FloatBuffer. When you've finished doing your stuff, save the ByteBuffer out to a WritableByteChannel.

  If you already have FloatBuffer it can be copied into the buffer from step 2 with a put.

  A low performance but easier way would be to use Float.floatToIntBit.

  (Watch for endianess, obviously.)