Why Spring boot controller not giving json reponse while using async?-CodePudding

I am making an application in spring boot. It was working fine until I made it asynchronous. I am not getting any error and no json response. I cannot figuring it out. How can i solve this. Please help me in figuring it out.

Post Repository:

@Repository
public interface PostRepository extends JpaRepository<Post,Long> {

@Async
Post findBySubject(String subject);
}

Post Service:

@Service
@Transactional
public class PostService {

@Autowired
private PostRepository postRepository;

@Async
public CompletableFuture<Post> find(String subject) throws ExecutionException, 
InterruptedException {
    System.out.println("Current Thread Name: " Thread.currentThread().getName());
    Post post = postRepository.findBySubject(subject);
    System.out.println("Current Thread Name: " Thread.currentThread().getName());
    return CompletableFuture.completedFuture(post);
  }
}

Post Controller:

@Slf4j
@RestController
@RequestMapping("/posts")
public class PostController {

@Autowired
private PostService postService;

@GetMapping
public CompletableFuture<Post> get(@RequestParam String subject){
    try {
        System.out.println("Current Thread Name: " Thread.currentThread().getName());
        return postService.find(subject);
    } catch (Exception e) {
        throw new IllegalStateException(e);
    }
  }
}

CodePudding user response：

Jpa Repository is not Async

@Async Post findBySubject(String subject); }

This is causing problem.

If you want it to work then you need to return CompletableFuture instead. Here I am referring a link from stack overflow : https://stackoverflow.com/a/38421923/11928455 (But again this is not recommanded)

So, remove @Async from repository. JpaRepository will not work asynchronously. If you need async repo then look into spring reactive repositories instead.