Custom Spring Validator Doesn't Get Injected

Question

The problem is this: Using Spring Boot, I have a hibernate entity (Message) and I want to create a custom validator for it.

import org.springframework.validation.Validator;
        
@Component
public class MessageValidator implements Validator {
@Override
    public boolean supports(Class<?> clazz) {
        return Message.class.isAssignableFrom(clazz);
    }

    @Override
    public void validate(Object target, Errors errors) {
    ... Do work here ...
    }
}

Then, I have a service

@Service
public class MessagesService {

    @Autowired
    Validator validator;

    public void doSomething(Message m) {
        Errors e = new BeanPropertyBindingResult(new Object(), "dummy");
        this.validator.validate(m, e);
    }
}

The problem is that the call to this.validator.validate(m, e); never makes it to my implementation.

My pom.xml has (amongst others):

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

So, am I missing something glaringly obvious here? If I name the validator component and I qualify the reference in the service, it's all good. But I'm expecting the Spring wiring to provide the proper validator for the type of object I call for. Or is this expectation too much?

Answer 1

Problem must be with your Autowiring.

Since you are using interface here, it could autowire the default (one of the implementation provided by Spring) instance.

  @Autowired
  Validator validator;

Solution:

1. Use MessageValidator instead of Validator

    @Autowired
    MessageValidator validator;

OR 2. Use qualified name:

    @Autowired
    @Qualifier(value = "messageValidator") //note lowercase m
    Validator validator;