SpringBoot JPA Interface's save() and delete() not working with ArrayList or Long

Question

I am following a tutorial that uses SpringBoot 1.3. I am on the latest release of SpringBoot 2.0. I am working on creating an REST API. I need help adapting the 1.3 code to 2.0 compliance as save() and delete() now expect objects over long ids. How do I need to rewrite the interface to accept long id' and 'ArrayList?

Here's the code as it stands:

The Base Object

@Entity
public class HotelBooking {

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
private long id; // could be Long

private String hotelName;
private double pricePerNight;
private int nbOfNights;

public HotelBooking(){} 

public HotelBooking(String hotelName, double pricePerNight, int nbOfNights) {
    this.hotelName = hotelName;
    this.pricePerNight = pricePerNight;
    this.nbOfNights = nbOfNights;
}
// getters omitted
}

The Interface

@Repository
public interface BookingRepository extends JpaRepository<HotelBooking, Long> {
data/jpa/docs/2.1.0.M1/reference/html/
    List<HotelBooking> findByPricePerNightLessThan(double price);
}

Using a long id to delete an entry in the database

@RequestMapping(value = "/delete/id")
public List<HotelBooking> remove(@PathVariable long id) {
    bookingRepository.delete(id);
    return bookingRepository.findAll();
}

Trying to save an ArrayList object to the database

 @Override
    public void run(String... strings) throws Exception {

        List<HotelBooking> bookings = new ArrayList<>();

        bookings.add(new HotelBooking("Marrior", 200.50, 3));
        bookings.add(new HotelBooking("Ibis", 90, 4));
        bookings.add(new HotelBooking("Novotel", 140.74, 1));

        bookingRepository.save(bookings);
    }

The Problem

The above do not work in SpringBoot 2.0 anymore. When trying to delete via ID I get an error saying - Error:(61, 34) java: incompatible types: long cannot be converted to romaniancoder.booking.HotelBooking It is now expecting an object instead of a long id to find an object in the database.

When trying to save an ArrayList I get this error - Error:(40, 26) java: method save in interface org.springframework.data.repository.CrudRepository<T,ID> cannot be applied to given types; required: S found: java.util.List<romaniancoder.booking.HotelBooking> reason: inferred type does not conform to upper bound(s) inferred: java.util.List<romaniancoder.booking.HotelBooking> upper bound(s): romaniancoder.booking.HotelBooking It's as if it needs a class extended or something to work? I am not sure...

After reading the Spring Docs I don't understand why this changed and how I can write code to accept a long id to find something in the database. I don't understand how to adapt save() to accept ArrayLists.

Answer 1

You can use repository.deleteById(Long) and repository.saveAll(ArrayList). These methods are introduced in SpringBoot 2.0.