In Java, when I write to a file with a DataOutputStream, how do I determine the endian of the data being written?

Question

I use a DataOutputStream to write to a file, however I want to change the endian of the data.

This is how I write byte data to a file (by default it is output by default by default)

 public void generateBinObjFile(String outputFile) try { // Create file DataOutputStream stream = new DataOutputStream( new FileOutputStream(outputFile)); stream.writeShort(this.quantize(this.xComponents.get(index), //<-- Short is written in little Endian this.min_x, this.max_x) - 32768); } // catch statements here 

Is there a way to define Endian how byte data is written in Java?

Answer 1

You cannot do this with a DataOutputStream , which always uses a large endian.

You can use the ByteBuffer , which you can call order() to influence how it reads and writes data.

You can use ByteBuffer either to prepare the byte[] , which you will write with the classic OutputStream later, or completely switch to NIO and use any WritableByteChannel to write

Answer 2

You can use com.google.common.io.LittleEndianDataOutputStream from

http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/io/LittleEndianDataOutputStream.html

or copy this class: http://www.cafeaulait.org/books/javaio/ioexamples/07/LittleEndianOutputStream.java

Answer 3

You cannot :

Records a brief description of the underlying output stream as two bytes with a high byte.

All multi-byte methods work like this. If you need it the other way around, you need to write bytes yourself.

Answer 4

It outputs data in a manner that is read by DataInputStream.

If you need to worry about content, you should not use Data * Stream.

Answer 5

All answers are given correctly. However, you can take the source of DataOutputStream, insert it into a new class and reverse the byte order in different writeShort, writeLong, etc. (Or at least the ones you need). This is not such a difficult job.

Obviously, you cannot use it to communicate with a DataInputStream on the other hand, but I suppose you need to write to a file or socket with a program on the other side, so you do not need a DataInputStream.