public interface UserService {

    Long createUser(UserDto userDto);

    void updateUser(UserDto userDto);

}

​

@Service

public class UserServiceImpl implements UserService {

​

    private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();

​

    @Autowired

    private UsersRepository usersRepository;

​

    @Autowired

    private KafkaTemplate<Long, String> kafkaTemplate;

​

    @Override

    public Long createUser(UserDto userDto) {

        Users user = new Users();

        user.setFirstname(userDto.getFirstname());

        user.setLastname(userDto.getLastname());

        user.setEmail(userDto.getEmail());

        return this.usersRepository.save(user).getId();

    }

​

    @Override

    @Transactional

    public void updateUser(UserDto userDto) {

        this.usersRepository.findById(userDto.getId())

                .ifPresent(user -> {

                    user.setFirstname(userDto.getFirstname());

                    user.setLastname(userDto.getLastname());

                    user.setEmail(userDto.getEmail());

                    this.raiseEvent(userDto);

                });

    }

​

    private void raiseEvent(UserDto dto){

        try{

            String value = OBJECT_MAPPER.writeValueAsString(dto);

            this.kafkaTemplate.sendDefault(dto.getId(), value);

        }catch (Exception e){

            e.printStackTrace();

        }

    }

}