Spring-Boot How to properly inject javax.validation.Validator

Question

I've got a problem injecting the Validator into the spring application bean when attempting to validate a model using JSR-303 (hibernate-validator)

My main configuration class is:

@EnableAutoConfiguration
@EnableWebMvc // <---
@EnableJpaRepositories("com.example")
@EntityScan("com.example")
public class MainConfiguration {

According to the javadocs:

/**
 * Provide a custom {@link Validator} instead of the one created by default.
 * The default implementation, assuming JSR-303 is on the classpath, is:
 * {@link org.springframework.validation.beanvalidation.LocalValidatorFactoryBean}.
 * Leave the return value as {@code null} to keep the default.
 */
Validator getValidator();

Hibernate-validator is on the classpath. I'm trying to inject it into the Repository:

@Repository
public class UserRepositoryImpl implements UserRepositoryCustom    {

    @Autowired
    private Validator validator;

Exception being thrown:

 No qualifying bean of type [javax.validation.Validator] found for dependency:

UPDATE:

The partial work-around for this is to define this in the main configuration class:

  @Bean
    public Validator validator() {

        return new org.springframework.validation.beanvalidation.LocalValidatorFactoryBean();
    }

But integration tests (the ones which require org.springframework.test.context.web.WebAppConfiguration; annotation and use validation logic) fail.

Answer 1

You need to declare a bean of type LocalValidatorFactoryBean like this:

<bean id="validator"
    class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"/>

in XML or

@Bean
public javax.validation.Validator localValidatorFactoryBean() {
   return new LocalValidatorFactoryBean();
}

in Java Config.

Edit:

It is important to understand that if JPA is being used and is backed by Hibernate, then Hibernate will try to automatically validate your Beans as well as the Spring Framework. This can lead to the problem of javax.validation.ValidationException: HV000064: Unable to instantiate ConstraintValidator because Hibernate doesn't know about the Spring Context and as far as I can tell there is no way to tell it, not even with the LocalValidatorFactoryBean. This causes the Validator's to run twice. One correctly, and once that fails.

In order to disable the default Hibernate ORM validation, the following property for Spring needs to be set:

spring.jpa.properties.javax.persistence.validation.mode=none

I updated this example, because it was the one I kept finding over and over again about the Validator's not being injected, and it turns out this was the problem I faced.

This part of the Spring documentation has all the details

Answer 2

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = {LocalValidatorFactoryBean.class, ...})
@SpringBootTest
public class TestClass{
     
    @Autowired
    private Validator validator;

    @Test
    public void testValidator(){
      ...logic...
      validator.validate(...);
    }
 }

Recently ran into this issue (9/26/2023). My goal was to create a unit test where I test out the validation annotations I have on some POJOs. My validation includes the use of custom Constraint Validation Annotations as well as javax.validation annotations. Since my goal was to actually just run some validation tests against various inputs I didn't want these validation classes mocked out. I actually needed them in the test context. By default, Spring won't run the typical application boot up process where component scanning is performed and the application context is resolved. You can include the @SpringBootTest annotation test if you want that process to be performed. But this should only be done sparingly because you are essentially starting the entire application, which for my use case was not necessary. My situation is a little special in that I have some wrapper and base classes my company likes us to use. One of them implements the Spring Validator interface and also Autowires the validator interface. This was problematic as the class would call ValidationUtils.invoke(validator, target, errors) in its own overridden validate method, but since this was the only implementation of the Validator interface present in the context, it would map what was supposed to be the default validator to itself resulting in a stack overflow exception when calling the validate method of the base wrapper class. In production, the autowired dependency to a validator resolves to the default implementation, LocalValidatorFactoryBean. So in short, this needs to be added to the context. When using the ContextConfiguration annotation and the SpringBootTest annotation, we are specifying the classes to be added to the application context. I tried this also using a static TestConfiguration block in my test class but this didn't resolve my issue correctly, which is what the other solutions show.