How to combine JSR-303 and Spring Validator class in a service layer?

Question

I have some model class

public class Account {

    @Email
    private String email;

    @NotNull
    private String rule;
}

and spring-validator

public class AccountValidator implements Validator {

    @Override
    public boolean supports(Class aClass) {
        return Account.class.equals(aClass);
    }

    @Override
    public void validate(Object obj, Errors errors) {
        Account account = (Account) obj;
        ValidationUtils.rejectIfEmpty(errors, "email", "email.required");
        ValidationUtils.rejectIfEmpty(errors, "rule", "rule.required");

        complexValidateRule(account.getRule(), errors);
    }

    private void complexValidateRule(String rule, Errors errors) {
        // ...
    }
}

I run in my service

AccountValidator validator = new AccountValidator();
Errors errors = new BeanPropertyBindingResult(account, "account");
validator.validate(account, errors);

Can I add to my validation process constraints @Email, @NotNull (JSR-303) and don't describe these rules in AccountValidator?

I know how works @Valid in spring-controllers, but what's about service layer? Is it possible? How to do such kind of validation in a proper way? May I should use Hibernate Validator?

Answer 1

Spring provides an Adapter to merge both validation APIs. See the current Spring JavaDoc for more information.

An possible implementation would be

public class AccountValidator implements Validator {

  private final SpringValidatorAdapter validator;

  public AccountValidator(SpringValidatorAdapter validator) {
      super();
      this.validator = validator;
  }

  @Override
  public boolean supports(Class aClass) {
      return Account.class.equals(aClass);
  }

  @Override
  public void validate(Object obj, Errors errors) {

      //jsr303
      validator.validate(obj, errors);

      //custom rules
      Account account = (Account) obj;
      complexValidateRule(account.getRule(), errors);
  }

  private void complexValidateRule(String rule, Errors errors) {
      // ...
  }
}