CODEWITHSUNDEEP
jpaspring-data-jpa
mrom
mrom

Reputation: 83

Avoiding loading LAZY collection in Spring Data Jpa

I have following relationship:

@Entity class Shop {
@OneToMany(mappedBy = "shop", fetch = LAZY)
private List<Employee> employees = new LinkedList<>();
}

and

@Entity class Employee {
@ManyToOne
private Shop shop;
}

I've declared Spring Data repository like this:

public interface ShopRepository extends JpaRepository<Shop, Long> {}

Calling ShopRepository#findOne(id) method forces fetching of the List<Employee> employees which is LAZY relationship.

I have service which uses Shop repository:

@Service
@Transactional(readOnly = true)
public class ShopService {

private final ShopRepository shopRepository;

@Autowired
public ShopService(ShopRepository shopRepository) {
    this.shopRepository = shopRepository;
}
public Shop find(Long id) {
    return shopRepository.findOne(id);
}

} The service method is called within another controller method:

@RequestMapping(value = "api/schedule/{shopId:[0-9]+}/{date:\\d{4}-\\d{2}-\\d{2}}", method = RequestMethod.GET)
@ResponseBody
public Schedule getSchedule(@PathVariable Long shopId,
                            @PathVariable @DateTimeFormat(pattern = "yyyy-MM-dd") LocalDate date) {
    Schedule schedule = scheduleService.findSchedule(shopId, date);
    if(schedule != null)
        return schedule;
    else {
        Shop shop = shopService.find(shopId);
        Schedule empty = new Schedule(shop, date);
        return empty;
    }
}

How to get rid of fetching employees relationship?

Upvotes: 3

Views: 2498

Answers (1)

mrom
mrom

Reputation: 83

I found solution.

Actually I used @JsonManagedReference/@JsonBackRefernce on my entity to prevent cycling while marshaling to JSON. It causes fetching LAZY loading data. To avoid this you should add Hibernate4Module to MappingJackson2HttpMessageConverter.

More info at this post: Avoid Jackson serialization on non fetched lazy objects

Upvotes: 2

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