在 java 8 中使用 orElseThrow 抛出用户定义的异常时出错

Question

我正在尝试使用 orElseThrow java 8 命令引发自定义异常。但是我收到以下编译错误：

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; 
}

而我的自定义异常class，扩展RunTimeException的UserNotFoundException如下：

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

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

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

我在 orElseThrow 语句中收到此错误：

The method orElseThrow(Supplier) in the type Optional is not applicable for the arguments (UserNotFoundException)

这里的问题是什么以及如何通过 orElseThrow 抛出自定义用户定义的异常？

提前致谢。

Answer 1

应该是供应商：

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

在 java 8 中使用 orElseThrow 抛出用户定义的异常时出错

Error while throwing User defined exception using orElseThrow in java 8

java

throw

optional

java-8