如果数据库查询返回空值,那么抛出异常的正确方法是什么?我试图用.orElseThrow()
方法,但它不会编译:Spring CrudRepository .orElseThrow()
Meeting meeting = meetingRepository.findByMeetingId(meetingId).orElseThrow(new MeetingDoesNotExistException(meetingId));
编译器说:
“他法orElseThrow(供应商)在类型可选不适用于参数(MeetingRestController.MeetingDoesNotExistException)
是否有可能与lambda表达式做到这一点?
铬udRepository:
import java.util.Optional;
import org.springframework.data.repository.CrudRepository;
public interface MeetingRepository extends CrudRepository<Meeting, Long>{
Optional<Meeting> findByMeetingId(Long id);
}
例外:
@ResponseStatus(HttpStatus.CONFLICT) // 409
class MeetingDoesNotExistException extends RuntimeException{
public MeetingDoesNotExistException(long meetingId){
super("Meeting " + meetingId + " does not exist.");
}
}
工作!谢谢! – szxnyc 2014-11-04 04:36:39