我有我的 RequestParam，我需要驗證它，但是 mu 自定義驗證不適用，我的控制器@RestController@Validatedclass ExchangeController {    private static final Logger logger = Logger.getLogger(ExchangeController.class.getName());    @SuppressWarnings("SpringJavaAutowiredFieldsWarningInspection")    @Autowired    @Qualifier("dataService")    private CurrencyExchangeService currencyExchangeService;    @RequestMapping(value = "/", method = RequestMethod.GET, produces = "application/json")    public Object converting(@RequestParam("fromCurrency") @NotNull @CurrencyValidation String fromCurrency,                             @RequestParam("toCurrency") @NotNull String toCurrency,                             @RequestParam("amount") @NotNull String amount) throws IOException {        BigDecimal convertedAmount = currencyExchangeService.convert(fromCurrency, toCurrency, new BigDecimal(amount));        return new ExchangeRateDTO(fromCurrency, toCurrency, new BigDecimal(amount), convertedAmount);    }}和自定義驗證public class ConstractCurrencyValidator implements            ConstraintValidator<CurrencyValidation, String> {        @Override        public void initialize(CurrencyValidation currency) {        }        @Override        public boolean isValid(String currency, ConstraintValidatorContext constraintValidatorContext) {            return currency != null && Currency.getAvailableCurrencies().contains(Currency.getInstance(currency));        }    }