How to combine two byte arrays [duplicate]

Question

I have two byte arrays and I am wondering how I would go about adding one to the other or combining them to form a new byte array.

Answer 1

You're just trying to concatenate the two byte arrays?

byte[] one = getBytesForOne(); byte[] two = getBytesForTwo(); byte[] combined = new byte[one.length + two.length];  for (int i = 0; i < combined.length; ++i) {     combined[i] = i < one.length ? one[i] : two[i - one.length]; } 

Or you could use System.arraycopy:

byte[] one = getBytesForOne(); byte[] two = getBytesForTwo(); byte[] combined = new byte[one.length + two.length];  System.arraycopy(one,0,combined,0         ,one.length); System.arraycopy(two,0,combined,one.length,two.length); 

Or you could just use a List to do the work:

byte[] one = getBytesForOne(); byte[] two = getBytesForTwo();  List<Byte> list = new ArrayList<Byte>(Arrays.<Byte>asList(one)); list.addAll(Arrays.<Byte>asList(two));  byte[] combined = list.toArray(new byte[list.size()]); 

Or you could simply use ByteBuffer with the advantage of adding many arrays.

byte[] allByteArray = new byte[one.length + two.length + three.length];  ByteBuffer buff = ByteBuffer.wrap(allByteArray); buff.put(one); buff.put(two); buff.put(three);  byte[] combined = buff.array(); 

Answer 2

You can do this by using Apace common lang package (org.apache.commons.lang.ArrayUtils class ). You need to do the following

byte[] concatBytes = ArrayUtils.addAll(one,two);