在java 8中使用orElseThrow引发用户定义的异常时出错[duplicate]

Question

我正在尝试使用orelsethrowJava8命令抛出一个自定义的Expetion。然而，我得到了以下编译错误：

public class UserInvitationServiceImpl implements UserInvitationService{

    @Autowired
    private UserRepository userRepository;

    @Override
    public void inviteUser(String email) throws UserNotFoundException {
        // TODO Auto-generated method stub
        if(email!= null && !email.isEmpty()) {
            Optional<User> optionalUser = userRepository.findByEmail(email);
            optionalUser.orElseThrow(new UserNotFoundException("User doesnt exist in system"));
        }
    }       
}

public interface UserInvitationService {   
    void inviteUser(String email) throws UserNotFoundException; 
}

和扩展RunTimeException的自定义异常类UserNotFoundException如下所示：

@ResponseStatus(value = HttpStatus.NOT_FOUND)
public class UserNotFoundException extends RuntimeException {

    /**
     * 
     */
    private static final long serialVersionUID = 9093519063576333483L;

    public UserNotFoundException( String message) {
        super(message);
    }    
}

提前道谢。

Answer 1

应为供应商：

.orElseThrow(() -> new UserNotFoundException("User doesnt exist in system"));