public class UuidUtils {
public static UUID asUuid(byte[] bytes) {
ByteBuffer bb = ByteBuffer.wrap(bytes);
long firstLong = bb.getLong();
long secondLong = bb.getLong();
return new UUID(firstLong, secondLong);
}
public static byte[] asBytes(UUID uuid) {
ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
bb.putLong(uuid.getMostSignificantBits());
bb.putLong(uuid.getLeastSignificantBits());
return bb.array();
}
}
@Test
public void verifyUUIDBytesCanBeReconstructedBackToOriginalUUID() {
UUID u = UUID.randomUUID();
byte[] uBytes = UuidUtils.asBytes(u);
UUID u2 = UuidUtils.asUuid(uBytes);
Assert.assertEquals(u, u2);
}
@Test
public void verifyNameUUIDFromBytesMethodDoesNotRecreateOriginalUUID() {
UUID u = UUID.randomUUID();
byte[] uBytes = UuidUtils.asBytes(u);
UUID u2 = UUID.nameUUIDFromBytes(uBytes);
Assert.assertNotEquals(u, u2);
}