Getting null values when using ConfigurationProperties on Spring boot

Question

I'm new to the Java world and Spring boot, and I'm trying to access some configuration values located in a YAML file through the ConfigurationProperties annotation.

But whenever I try to access a configuration value anywhere in a service, I get a null value.

Here's the application.yml file:

my_config:
  test: "plop"

Here's the ValidationProperties configuration class:

@Configuration
@ConfigurationProperties(prefix = "my_config")
public class ValidationProperties {

    @NotNull
    private String test;

    public void setTest(String test) {
        this.test = test;
    }

    public String getTest() {
        return this.test;
    }
}

A validator service that uses it:

@Service
public class MyValidator implements ConstraintValidator<MyConstraint, MyEntity> {

    @Autowired
    private ValidationProperties validationProperties;

    @Value("${my_config.test}")
    private String test;

    @Override
    public boolean isValid(MyEntity entity, ConstraintValidatorContext context) {

        System.out.println(this.test); // null value, why?
    }
}

I also added the @EnableConfigurationProperties annotation in my main class.

I'm not sure which annotation is supposed to do what, but I'm obviously missing something here. Also, if I try to access the value from the getter of the configuration file, I get an exception:

System.out.println(this.validationProperties.getTest());

will get me HV000028: Unexpected exception during isValid call.

did you include mvnrepository.com/artifact/org.springframework.boot/… — Daniel Jacob
– Daniel Jacob, Commented May 29, 2020 at 11:38

Alexander Nikolaev · Accepted Answer · 2020-07-24 14:54:40Z

2

Try adding @EnableConfigurationProperties(ValidationProperties.class) on your main application class or any other @Configuration class.

Also putting @Component annotation on ValidationProperties should work.

No need to inject value via @Value annotation, just access it via getter of injected validationProperties object

answered Jul 24, 2020 at 14:54

Alexander Nikolaev

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Comments

rvazquezglez · Accepted Answer · 2021-02-16 06:54:22Z

0

I got this error running a JUnit test on a SpringBoot app, what I was missing is the annotation @SpringBootTest

answered Feb 16, 2021 at 6:54

rvazquezglez

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Comments

Thomas · Accepted Answer · 2025-03-15 07:59:12Z

0

Looks like the application.yml is not read. If unsure add a syntax error to it, e.g. a line containing just a colon. The application then must not start.

Check spelling of the filename and make sure the file is located in the working directory of the application. When using an IDE this usually means the file must be put next to the src folder.

answered Mar 15 at 7:59

Thomas

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