커스텀 밸리데이션

DTO.java

@PasswordsNotEqual(
        passwordFieldName = "password",
        passwordVerificationFieldName = "passwordVerification"
)

NickNameNotEmpty.java

@Target( { TYPE, ANNOTATION_TYPE })
@Retention(RUNTIME)
@Constraint(validatedBy = PasswordsNotEmptyValidator.class)
@Documented
public @interface NickNameNotEmpty {
  String message() default "PasswordsNotEmpty";

  Class<?>[] groups() default {};

  Class<? extends Payload>[] payload() default {};

  String userFieldName() default "";

  String anonymousNickFieldName() default "";
}

NickNameNotEmptyValidator.java

import org.apache.commons.lang3.StringUtils;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class NickNameNotEmptyValidator  implements ConstraintValidator<NickNameNotEmpty, Object> {

  private String userFieldName;
  private String anonymousNickFieldName;

  @Override
  public void initialize(NickNameNotEmpty constraintAnnotation) {
    this.userFieldName = constraintAnnotation.userFieldName();
    this.anonymousNickFieldName = constraintAnnotation.anonymousNickFieldName();
  }

  @Override
  public boolean isValid(Object value, ConstraintValidatorContext context) {
    context.disableDefaultConstraintViolation();
    try {
      User user = (User) ValidatorUtil.getFieldValue(value, userFieldName);
      if(user!=null) return true;
      String anonNick = (String) ValidatorUtil.getFieldValue(value, anonymousNickFieldName);

      if (StringUtils.isBlank(anonNick)) {
        ValidatorUtil.addValidationError(anonymousNickFieldName, context);
        return false;
      }
    }
    catch (Exception ex) {
      throw new RuntimeException("Exception occurred during validation", ex);
    }
    return true;
  }

}

ValidatorUtil.java

/**
 * @author Petri Kainulainen
 */
public class ValidatorUtil {

    public static void addValidationError(String field, ConstraintValidatorContext context) {
        context.buildConstraintViolationWithTemplate(context.getDefaultConstraintMessageTemplate())
                .addNode(field)
                .addConstraintViolation();
    }

    public static Object getFieldValue(Object object, String fieldName) throws NoSuchFieldException, IllegalAccessException {
        Field f = object.getClass().getDeclaredField(fieldName);
        f.setAccessible(true);
        return f.get(object);
    }
}