Hibernate + MySQL - How can I get not guessable generated ID?

Question

How can I get entity ID (primary key) to be hard to guess?

Ideal would be 8 or 16 digit random unique number or String.

I tried UUID but it fails with my H2 tests because of reported bug ( https://github.com/h2database/h2database/issues/345 ).

Or if it's hard with ID... how can I get another column to be auto generated with random unique number while creating ?

I need random, hard to guess, unique ID per user for external API.

Thanks for any suggestions. :)

Answer 1

You can assign value to another column using @PrePersist annotation. Something like:

public class MyClass  {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    protected T id;

    @Column
    protected String clientKey;

    @PrePersist
    public void ensureClientKeyGenerated() {
          this.clientKey = UUID.randomUUID();  
    }

}