Spring Data JPA and QueryDSL

Question

I'm new to Spring data JPA and am trying to understand how to best use it with QueryDSL. Without QueryDSL, I would be able to simply create any queries in my SpringData interface with an @Query annotation.

In order to have the same experience using QueryDSL, from what I can see, I need to either create my own custom repository implementation and have my repo interface extend my custom implementation interface or put all my QueryDSL queries at a service layer which wraps my repo.

In the first case, I lose the ability to use any of the SD autogenerated methods (ex: findAll(QueryDSL predicate) ) in my custom repo since I don't have access to the actual repo object, and in the second case I am putting query logic at the service layer instead of at the repo layer.

Neither solution sounds particularly attractive to me. Is there a 3rd way that is more appropriate? Or am I misunderstanding how to properly use QueryDSL and Spring Data?

Thanks!

Eric

Answer 1

Probably the most convenient way is to let your repository interfaces simply extend QueryDslPredicateExecutor which adds the capability to simply pipe Querydsl Predicate objects into the repository and execute them standalone or alongside Pageable and Sort and the like.

If you really want to hide the combination of predicates into the repository layer (which is absolutely fine but actually serves a different purpose) you create a separate repository implementation class as described here and use QueryDslRepositorySupport as base class. In your implemented finder methods you can then just use the from(…), update(…) and delete(…) methods of the base class to easily construct and execute queries using the Querydsl meta-model.