利用Spring Boot和JPA创建GraphQL API

<dependency>
  <groupId>com.<a href="https://javakk.com/tag/graphql" rel="external nofollow"  target="_blank" >graphql</a>-java</groupId>
  <artifactId>graphql-spring-boot-starter</artifactId>
  <version>5.0.2</version>
</dependency>
<dependency>
  <groupId>com.graphql-java</groupId>
  <artifactId>graphql-java-tools</artifactId>
  <version>5.2.4</version>
</dependency>

//Define the Entity attribute
type Location {
 id: ID!
 name: String!
 address: String!
}
type Query {
 findAllLocations: [Location]!
}
type Mutation {
 newLocation(name: String!, address: String) : Location!
 deleteLocation(id:ID!) : Boolean
 updateLocationName(newName: String!, id:ID!) : Location!
}

//imports...
public interface LocationRepository extends CrudRepository<Location, Long> {
}

//imports...
@Component
public class Query implements GraphQLQueryResolver {
    private LocationRepository locationRepository;
    public Query(LocationRepository locationRepository) {
        this.locationRepository = locationRepository;
    }
    public Iterable<Location> findAllLocations() {
        return locationRepository.findAll();
    }
}

//imports...
@Component
public class Mutation implements GraphQLMutationResolver {
    private LocationRepository locationRepository;
    public Mutation(LocationRepository locationRepository) {
        this.locationRepository = locationRepository;
    }
    public Location newLocation(String name, String address) {
        Location location = new Location(name, address);
        locationRepository.save(location);
        return location;
    }
    public boolean deleteLocation(Long id) {
        locationRepository.deleteById(id);
        return true;
    }
    public Location updateLocationName(String newName, Long id) {
        Optional<Location> optionalLocation =
                locationRepository.findById(id);
        if(optionalLocation.isPresent()) {
            Location location = optionalLocation.get();
            location.setName(newName);
            locationRepository.save(location);
            return location;
        } else {
            throw new LocationNotFoundException("Location Not Found", id);
        }
    }

//imports...
public class LocationNotFoundException extends RuntimeException implements GraphQLError {
    private Map<String, Object> extensions = new HashMap<>();
    public LocationNotFoundException(String message, Long invalidLocationId) {
        super(message);
        extensions.put("invalidLocationId", invalidLocationId);
    }
    @Override
    public List<SourceLocation> getLocations() {
        return null;
    }
    @Override
    public Map<String, Object> getExtensions() {
        return extensions;
    }
    @Override
    public ErrorType getErrorType() {
        return ErrorType.DataFetchingException;
    }