how to compare the Java Byte[] array?

Question

public class ByteArr {

    public static void main(String[] args){
        Byte[] a = {(byte)0x03, (byte)0x00, (byte)0x00, (byte)0x00};
        Byte[] b = {(byte)0x         


        

Answer 1

Cause they're not equal, ie: they're different arrays with equal elements inside.

Try using Arrays.equals() or Arrays.deepEquals().

Answer 2

Try for this:

boolean blnResult = Arrays.equals(byteArray1, byteArray2);

I am also not sure about this, but try this may be it works.

Answer 3

I looked for an array wrapper which makes it comparable to use with guava TreeRangeMap. The class doesn't accept comparator.

After some research I realized that ByteBuffer from JDK has this feature and it doesn't copy original array which is good. More over you can compare faster with ByteBuffer::asLongBuffer 8 bytes at time (also doesn't copy). By default ByteBuffer::wrap(byte[]) use BigEndian so order relation is the same as comparing individual bytes.

.

Answer 4

You can also use org.apache.commons.lang.ArrayUtils.isEquals()

Answer 5

Arrays.equals is not enough for a comparator, you can not check the map contain the data. I copy the code from Arrays.equals, modified to build a Comparator.

class ByteArrays{
    public static <T> SortedMap<byte[], T> newByteArrayMap() {
        return new TreeMap<>(new ByteArrayComparator());
    }

    public static SortedSet<byte[]> newByteArraySet() {
        return new TreeSet<>(new ByteArrayComparator());
    }

    static class ByteArrayComparator implements Comparator<byte[]> {
        @Override
        public int compare(byte[] a, byte[] b) {
            if (a == b) {
                return 0;
            }
            if (a == null || b == null) {
                throw new NullPointerException();
            }

            int length = a.length;
            int cmp;
            if ((cmp = Integer.compare(length, b.length)) != 0) {
                return cmp;
            }

            for (int i = 0; i < length; i++) {
                if ((cmp = Byte.compare(a[i], b[i])) != 0) {
                    return cmp;
                }
            }

            return 0;
        }
    }
}

Answer 6

have you looked at Arrays.equals()?

Edit: if, as per your comment, the issue is using a byte array as a HashMap key then see this question.