UUID to byte[]

Question

Hello,
I don't understand how to convert a UUID object into a byte sequence (of same format as UUID.nameUUIDFromBytes(byte[]) takes in parameter)
I've coded i little method but it doesn't give me a correct byte array, i've tested the output with UUID.nameUUIDFromBytes(byte[]) and it doesn't return the original key.
protected byte[] encode(UUID key){
        ByteBuffer keyBuffer = ByteBuffer.allocate(16);
        keyBuffer.order(ByteOrder.BIG_ENDIAN);
        keyBuffer.putLong(key.getMostSignificantBits());
        keyBuffer.putLong(key.getLeastSignificantBits());
        return keyBuffer.array();
}Example :
public static void main(String args[]){
        UUID before = UUID.fromString("a53e607c-e9c7-475f-a938-9ae6331d85b1");
        byte b_uuid[] = encode(before);
        UUID after = UUID.nameUUIDFromBytes(b_uuid);
        System.out.println(before.toString()+" - > "+after.toString());
}Output : a53e607c-e9c7-475f-a938-9ae6331d85b1 - > 625c894f-dfa5-3b8e-b577-458d7d676fe0
Any idea ?

Answer 1

writing:
long hibits = id.getMostSignificantBits();
long lobits = id.getLeastSignificantBits();
// A. then just write the two longs...
// B. or if you really want byte[]s...
byte[] hibytes = new BigDecimal(hibits).toByteArray();
byte[] lobytes = new BigDecimal(lobits).toByteArray();reading:
// (B.) decode the byte[] to longs
long hibits = new BigInteger(hibytes).longValue();
long lobits = new BigInteger(lobytes).longValue();
// (A.) read two longs from your stream
id = new UUID(hibits, lobits);