Hibernate：无法通过 UUID 找到

Question

Im trying to use UUID's as ids for my database but I simply do not get it working.

First attempt was:

@Id
@GeneratedValue(generator = "hibernate-uuid")
@GenericGenerator(name = "uuid", strategy = "uuid4")
private UUID id;

but this is generating some ugly byte code. So I added a type annotation:

@Id
@GeneratedValue(generator = "hibernate-uuid")
@GenericGenerator(name = "uuid", strategy = "uuid4")
@Type(type="org.hibernate.type.UUIDCharType")
private UUID id;

with this I get a character representation in my mysql database but querying the database using my repository:

public interface CommentsRepository extends CrudRepository<Comment, UUID> {

    Comment findById(final UUID imageId);
}

wont find any result - even if an entry with the given UUID exists it wont return the result. Even if I use plain SQL directly on my database it wont find any result.

Is there something else I need to do to get UUID's working?

EDIT

Trying this:

@Data
@Entity
public class Comment implements Serializable {

    @Id
    @GeneratedValue(generator = "uuid2")
    @GenericGenerator(name = "uuid2", strategy = "uuid2")
    @Type(type = "uuid-char")
    private UUID id;
}

and adding some default values:

@Component
@Slf4j
public class CommentsSampleData implements CommandLineRunner {

    private final CommentsRepository repository;

    @Autowired
    public CommentsSampleData(final CommentsRepository repository) {
        this.repository = repository;
    }

    @Override
    public void run(String... args) {
        repository.save(new Comment());
        repository.save(new Comment());
        repository.save(new Comment());
        repository.save(new Comment());
    }
}

Results in the following table:

performing:

SELECT * FROM comment WHERE id = 'b076a9f7-7e9e-4f5a-91f8-e66c7d076fac' 

results in:

which means no result but there should be one. Using jpa also does not return anything.

Answer 1

Have you tried this uuid annotation maybe:

@Id
GeneratedValue(generator = "uuid2")
@GenericGenerator(name = "uuid2", strategy = "uuid2")
@Column(columnDefinition = "BINARY(16)")
private UUID id;

This sample should work with java.util.UUID .

EDIT: I've read that you could run into problems with having a binary type set, so you could also try with explicitly setting it to a char uuid with:

@Type(type="uuid-char")

Answer 2

It works with the following:

@Id
@GeneratedValue(generator = "uuid4")
@GenericGenerator(name = "UUID", strategy = "uuid4")
@Type(type = "org.hibernate.type.UUIDCharType")
@Column(columnDefinition = "CHAR(36)")
private UUID id;

Answer 3

When I was using the 2.1.212 version of H2 in memory database, I faced the same problem on my project. I converted H2 version from 2.1.212 to 1.4.200 and it solved