Java Top

Get started with Spring 5 and Spring Boot 2, through the Learn Spring course:

> CHECK OUT THE COURSE

1. Overview

In this short tutorial, we'll see how to convert between a byte array and UUID in Java.

2. Convert UUID to Byte Array

We can easily convert a UUID to a byte array in plain Java:

public static byte[] convertUUIDToBytes(UUID uuid) {
    ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
    bb.putLong(uuid.getMostSignificantBits());
    bb.putLong(uuid.getLeastSignificantBits());
    return bb.array();
}

3. Convert Byte Array to UUID

Converting a byte array to UUID is just as simple:

public static UUID convertBytesToUUID(byte[] bytes) {
    ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
    long high = byteBuffer.getLong();
    long low = byteBuffer.getLong();
    return new UUID(high, low);
}

4. Test Our Methods

Let's test our methods:

UUID uuid = UUID.randomUUID();
System.out.println("Original UUID: " + uuid);

byte[] bytes = convertUUIDToBytes(uuid);
System.out.println("Converted byte array: " + Arrays.toString(bytes));

UUID uuidNew = convertBytesToUUID(bytes);
System.out.println("Converted UUID: " + uuidNew);

The result will look something like:

Original UUID: bd9c7f32-8010-4cfe-97c0-82371e3276fa
Converted byte array: [-67, -100, 127, 50, -128, 16, 76, -2, -105, -64, -126, 55, 30, 50, 118, -6]
Converted UUID: bd9c7f32-8010-4cfe-97c0-82371e3276fa

5. Conclusion

In this quick tutorial, we've learned how to convert between a byte array and UUID in Java.

As always, the example code from this article can be found over on GitHub.

Java bottom

Get started with Spring 5 and Spring Boot 2, through the Learn Spring course:

>> CHECK OUT THE COURSE
Generic footer banner
Comments are closed on this article!