I'm trying to implement some custom validation logic for a spring boot endpoint using a combination of JSR-303 Bean Validation API
and Spring's Validator
.
Based on the Validator class diagram it appears to be possible to extend one of CustomValidatorBean
, SpringValidatorAdapter
or LocalValidatorFactoryBean
to add some custom validation logic into an overridden method validate(Object target, Errors errors)
.
However, if I create a validator extending any of these three classes and register it using @InitBinder
its validate(Object target, Errors errors)
method is never invoked and no validation is performed. If I remove @InitBinder
then a default spring validator performs the JSR-303 Bean Validation
.
Rest controller:
@RestController
public class PersonEndpoint {
@InitBinder("person")
protected void initBinder(WebDataBinder binder) {
binder.setValidator(new PersonValidator());
}
@RequestMapping(path = "/person", method = RequestMethod.PUT)
public ResponseEntity<Person> add(@Valid @RequestBody Person person) {
person = personService.save(person);
return ResponseEntity.ok().body(person);
}
}
Custom validator:
public class PersonValidator extends CustomValidatorBean {
@Override
public boolean supports(Class<?> clazz) {
return Person.class.isAssignableFrom(clazz);
}
@Override
public void validate(Object target, Errors errors) {
super.validate(target, errors);
System.out.println("PersonValidator.validate() target="+ target +" errors="+ errors);
}
}
If my validator implements org.springframework.validation.Validator
then its validate(Object target, Errors errors)
method is called but JSR-303 Bean Validation
is not performed prior to it. I can implement my custom JSR-303 validation similar to the way SpringValidatorAdapter
implements its JSR-303 Bean Validation
but there has to be a way to extend it instead:
@Override
public void validate(Object target, Errors errors) {
if (this.targetValidator != null) {
processConstraintViolations(this.targetValidator.validate(target), errors);
}
}
I have looked at using custom JSR-303 constraints to avoid using org.springframework.validation.Validator
all together but there must be a way to make a custom validator work.
Spring validation documentation is not super clear on combining the two:
An application can also register additional Spring Validator instances per DataBinder instance, as described in Section 9.8.3, “Configuring a DataBinder”. This may be useful for plugging in validation logic without the use of annotations.
And then later on it touches on configuring multiple Validator instances
A DataBinder can also be configured with multiple Validator instances via dataBinder.addValidators and dataBinder.replaceValidators. This is useful when combining globally configured Bean Validation with a Spring Validator configured locally on a DataBinder instance. See ???.
I'm using spring boot 1.4.0.
Best Answer
This problem can be solved extending the LocalValidatorFactoryBean, you can override the
validate
method inside this class giving any behavior that you want.In my case I need to use JSR-303 AND custom validators for same model in different methods in same Controller, normally is recommended to use @InitBinder, but it is not sufficient for my case because InitBinder make a bind between Model and Validator (if you use @RequestBody InitBinder is just for one model and one validator per Controller).
Controller
Custom Validator
Class to be validate
CustomLocalValidatorFactoryBean
Configure application
Input to
/test
endpoint:Output from
/test
endpoint:Input to
/test2
endpoint:Output to
/test2
endpoint:I hope this help.