Can a bean use a custom validator annotation and output a custom validation error message?

Question

I need to validate a payload for my spring boot api. I created a custom validated annotation for a list of key-value pairs (specialAccommodations) which is dependent on another beans value (dressingRoom). specialAccommodations is stored as a List< Map<String, String> > in the venue bean. The validation requirements are different per dressing room and set accordingly. The validtor works and I'm able to confirm by debugging that it's returning the correct boolean in the isValid method. However, the message is always blank. Any ideas? Is it bad practice to put the custom validation annotation on the bean?

Payload

{
  "artist": {
    "name": "",
    "birthdate": "",
    "dressingRoom": ""
  },
  "venue": {
    "state": ""
    "specialAccommodations": [
      {
        "water": "sparkling",
        "snack": "chips",
        ...
      }
    ]
  }
}

Bean - maps the payload

@PayloadConstaints(message = "Error validating special accommodations")
public class payloadBean{
  
  @Valid
  private artistBean;
  
  @Valid
  private venueBean;
}

Validator Annotation

@Constraint(validatedBy = PayloadValidator.class)
@Target({TYPE, FIELD, ANNOTATION_TYPE})
@Retention(RUNTIME)
@Documented
public @iterface PayloadConstaints{
  String message() default "{}";
  
  Class<?>[] groups() default {};

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

I am unable to use the annotation in the controller and need access to the artist and venue beans to validate properly. The class that handles the validation logic implements ConstraintValidator<PayloadConstraint, payloadBean>.

I followed this example and it worked: https://blog.tericcabrel.com/write-custom-validator-for-body-request-in-spring-boot/#:~:text=Create%20custom%20validator,used%20on%20the%20input%20value.

However, they are validating a value from the bean, not the bean itself.

milo · Accepted Answer · 2022-11-01 16:32:46Z

0

The default message should be updated. You must add to the list of validation errors in the validator class. The property node is the bean and the bean property you want to associate the error message with. Here are the following code changes I made:

Validator Annotation

String message() default "There is an error with the given payload.";

PayloadValidator Class

@Override
public boolean isValid(PayloadBean bean, ConstraintValidatorContext context){
   boolean isValid;      
   // logic here
  
  // assume the artistBean has a String name
  context.buildConstraintViolationWithTemplate(context.getDefaultConstraintMessageTemplate()).addPropertyNode("artistBean.name").addConstraintViolation();
return isValid;
}

answered Nov 1, 2022 at 16:32

milo

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Can a bean use a custom validator annotation and output a custom validation error message?

Payload

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Validator Annotation

PayloadValidator Class

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