我正在嘗試在https://symfony.com/doc/current/validation/custom_constraint.html中描述的 Symfony 4.4 項(xiàng)目中創(chuàng)建自定義驗(yàn)證器我添加了下一個(gè)文件：src/Validator/Constraints/PhoneNumber.php<?phpnamespace App\Validator\Constraints;use Symfony\Component\Validator\Constraint;/** * @Annotation */class PhoneNumber extends Constraint{    public $message = 'The string contains an illegal character: it can only contain letters or numbers.';}src/Validator/Constraints/PhoneNumberValidator.phpnamespace App\Validator\Constraints;use Symfony\Component\Validator\Constraint;use Symfony\Component\Validator\ConstraintValidator;use Symfony\Component\Validator\Exception\UnexpectedTypeException;use Symfony\Component\Validator\Exception\UnexpectedValueException;class PhoneNumberValidator extends ConstraintValidator{    public function validate($value, Constraint $constraint)    {        dd('er wordt gevalideerd!');        if (!$constraint instanceof PhoneNumber) {            throw new UnexpectedTypeException($constraint, PhoneNumber::class);        }        // custom constraints should ignore null and empty values to allow        // other constraints (NotBlank, NotNull, etc.) take care of that        if (null === $value || '' === $value) {            return;        }        if (!is_string($value)) {            // throw this exception if your validator cannot handle the passed type so that it can be marked as invalid            throw new UnexpectedValueException($value, 'string');            // separate multiple types using pipes            // throw new UnexpectedValueException($value, 'string|int');        }        if (!preg_match('/^[a-zA-Z0-9]+$/', $value, $matches)) {            // the argument must be a string or an object implementing __toString()            $this->context->buildViolation($constraint->message)                ->setParameter('{{ string }}', $value)                ->addViolation();        }    }}在我嘗試了上述方法之后，驗(yàn)證器沒(méi)有響應(yīng)......所以接下來(lái)我嘗試將驗(yàn)證器約束添加到我的實(shí)體聯(lián)系人中。這也行不通。有人看到我做錯(cuò)了什么或?qū)ξ铱梢試L試什么有建議？提前致謝！