Java spring data mongodb: UUID as entity ID in mongodb

Question

I'm building spring boot application with spring-boot-starter-data-mongodb:

I have an etity which looks like:

@Document(collection = "nodes")
@Data
@Builder
public class Node {

    @Id
    UUID id;

    String info;
}

and repository interface:

public interface NodesRepository extends MongoRepository<Node, UUID> {
}

The problem is that when I insert Node object with empty id field application throws exception with the following message:

Cannot autogenerate id of type java.util.UUID for entity of type model.Node!

I know that out of box spring mongodb supports String and BigInteger id types for autogeneration.

So I want to know is it possible to use UUID as type for my id field or not? Can I create some type of custom MappingMongoConverter for my entity?

Answer 1

You can solve this problem by creating a CustomRepository

@NoRepositoryBean
public interface CustomMongoRepository<T extends BaseEntity>
    extends MongoRepository<T, Long> {
}

---

public class CustomMongoRepositoryImpl<T extends BaseEntity>
        extends SimpleMongoRepository<T, Long> implements CustomMongoRepository<T> {

    CustomMongoRepositoryImpl(
        MongoEntityInformation<T, Long> entityInformation,
        MongoOperations mongoOperations) {

        super(entityInformation, mongoOperations);
    }

    @Override
    public <S extends T> S insert(S entity) {
        generateId(entity);
        return super.insert(entity);
    }

    @Override
    public <S extends T> List<S> insert(Iterable<S> entities) { ... }

    @Override
    public <S extends T> S save(S entity) { ... }

    @Override
    public <S extends T> List<S> save(Iterable<S> entities) { ... }

    protected <S extends T> void generateId(S entity) { ... }

}

---

@SpringBootApplication
@EnableMongoRepositories(repositoryBaseClass = CustomMongoRepositoryImpl.class)
public class Application {
    ...
}

I hope this is helpful.

Answer 2

I would do this by implementing an onBeforeSave listener, or possibly an onBeforeConvert listener, as detailed in the documentation here.