JPA: How to select a binary(16) UUID by a String UUID? - spring

Question

I have the following Entity:
#Data
#Entity
public class Comment implements Serializable {
#Id
#GeneratedValue(generator = "uuid4")
#GenericGenerator(name = "UUID", strategy = "uuid4")
#Column(columnDefinition = "BINARY(16)")
private UUID id;
#Column(columnDefinition = "BINARY(16)")
private UUID imageId;
private Instant creationTime;
private String text;
}
And a CRUD repo:
public interface CommentsRepository extends CrudRepository<Comment, UUID> {
List<Comment> findAllByImageId(final UUID imageId);
}
I add some example data:
#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) {
createComment("617220ff-1642-4490-b589-869e7978c5e0", Instant.now(), "comment1");
createComment("617220ff-1642-4490-b589-869e7978c5e0", Instant.now(), "comment2");
createComment("617220ff-1642-4490-b589-869e7978c5e0", Instant.now(), "comment3");
createComment("e3a8aa57-6937-4f9e-b117-78bafe61b718", Instant.now(), "comment1");
}
private void createComment(
final String imageId,
final Instant creationTime,
final String text) {
final Comment comment = new Comment();
comment.setImageId(UUID.fromString(imageId));
comment.setCreationTime(creationTime);
comment.setText(text);
log.info("save comment: {}", comment);
repository.save(comment);
}
}
So the data in my table looks like the following:
So what is the best way now to select by those binary UUID's?
I will get string UUID's from the frontend So I guess I somehow need to convert those Strings to Binaryies. Whats the best way to do so so that it also works with ids and primary keys.
Example endpoint:
#Slf4j
#RestController
public class CommentsController {
private final CommentsService service;
public CommentsController(final CommentsService service) {
this.service = service;
}
#GetMapping(value = "/comments", produces = MediaType.APPLICATION_JSON_VALUE)
public List<Comment> getComments(#RequestParam("imageId") final UUID imageId) {
log.info("get comments by imageId: {}", imageId);
String existingIds = service.findAll().stream()
.map(Comment::getImageId)
.map(UUID::toString)
.collect(Collectors.joining(","));
log.info("Image Id Passed: {}", imageId);
log.info("Existing image ids: {}", existingIds);
String resultIds = service.findAllByImageId(imageId).stream()
.map(Comment::getImageId)
.map(UUID::toString)
.collect(Collectors.joining(","));
log.info("Result image ids: {}", resultIds);
return service.findAllByImageId(imageId);
}
}
When I now do a request:
localhost:8080/comments?imageId=617220ff-1642-4490-b589-869e7978c5e0
I get no result even though the UUID exists but not as string, it exists as binary(16) in the database:
d.f.a.c.service.CommentsController : Image Id Passed: 617220ff-1642-4490-b589-869e7978c5e0
d.f.a.c.service.CommentsController : Existing image ids: 617220ff-1642-4490-b589-869e7978c5e0,617220ff-1642-4490-b589-869e7978c5e0,617220ff-1642-4490-b589-869e7978c5e0,e3a8aa57-6937-4f9e-b117-78bafe61b718
d.f.a.c.service.CommentsController : Result image ids:

Answer 1

It is working as expected without any issue and it is auto converted between UUID and binary.
I recommend trying the following to make sure that id genuinely exists in database.
#GetMapping(value = "/comments", produces = MediaType.APPLICATION_JSON_VALUE)
public Iterable<Comment> getComments(#RequestParam("imageId")
final UUID imageId) {
log.info("get comments by imageId: {}", imageId);
String existingIds = service.findAll()
.map(Comment::getImageId)
.map(UUID::toString)
.collect(Collectors.joining(","));
log.info("Image Id Passed : {}", imageId);
log.info("Existing image ids : {}", existingIds);
return service.findAllByImageId(imageId);
}