在服务中引发异常时，哪种做法更好？

Question

I'm working on a Spring Boot CRUD RESTful API and i'm trying to define the best way of doing certain things, for instance:

This is my List user by its id endpoint service:

@Service
public class DetailUserService {

    @Autowired
    UserRepository repository;

    public Optional<User> listUser(Long id) {

        Optional<User> user = repository.findById(id);
        if (!user.isPresent()) {
            throw new UserNotFoundException(id);
        } else {
            return repository.findById(id);
        }
    }
}

And this is another way of writing it:

@Service
public class DetailUserService {

    @Autowired
    UserRepository repository;

    public User listUser(Long id) {
        return repository.findById(id)
                .orElseThrow(() -> new UserNotFoundException(id));
    }
}

Both ways work but how do i know which is better?

Answer 1

Using java-8 is always a better choice for less code and more readable code.
You can use below tyle of as you mentioned it as your second option. Using the Optional.orElseThrow() method represents another elegant alternative to the isPresent()-get() pair

You can find out more here https://dzone.com/articles/using-optional-correctly-is-not-optional

@Service
public class DetailUserService {

    @Autowired
    UserRepository repository;

    public User listUser(Long id) {
        return repository.findById(id)
                .orElseThrow(() -> new UserNotFoundException(id));
    }
}