Split jackson configuration into separate properties - spring-boot

Question

I'm using Spring Boot 2.2.5.RELEASE and would like to split my application.properties into separate files. There are already similar questions on StackOverflow but none of them seem to work for configuring Jackson.
My current non working solution is the following:
root/
- application.properties (without Jackson configuration)
- jackson-configuration.properties (includes Jackson configuration)
Jackson configuration class:
#Configuration
#PropertySource("/jackson-configuration.properties")
public class JacksonConfiguration {
}
Please note, I've tried different ways to specify the path including:
"/jackson-configuration.properties"
"jackson-configuration.properties"
"classpath:/jackson-configuration.properties"
"classpath:jackson-configuration.properties"
Spring Boot does not seem to use the configuration. If I copy it over into the application.properties - it works.
Content of jackson-configuration.properties:
spring.jackson.property-naming-strategy=SNAKE_CASE
spring.jackson.mapper.sort-properties-alphabetically=true
spring.jackson.deserialization.fail-on-unknown-properties=true
spring.jackson.parser.strict-duplicate-detection=true
spring.jackson.time-zone=Europe/Zurich
My application is annotated with #SpringBootApplication , so it should scan for additional properties.
/edit
I just realized the problem is the testing, not the productive code itself. If I start the application it works. What doess not work is testing with #JsonTest. I can fix this problem by adding the following line to my tests #ContextConfiguration(classes = {JacksonConfiguration.class}). But in turn, this causes the annotation #JsonComponent to stop working but only for the #JsonTest annotated classes.

Answer 1

See the documentation here. Here is an excerpt from the documentation
In order to resolve ${...} placeholders in definitions or
#Value annotations using properties from a PropertySource, you must
ensure that an appropriate embedded value resolver is registered in
the BeanFactory used by the ApplicationContext. This happens
automatically when using in XML. When
using #Configuration classes this can be achieved by explicitly
registering a PropertySourcesPlaceholderConfigurer via a static #Bean
method.
You need to create a bean like this
#Bean
public static PropertySourcesPlaceholderConfigurer devPropertyPlaceholderConfigurer() throws IOException {
PropertySourcesPlaceholderConfigurer configurer = new PropertySourcesPlaceholderConfigurer();
configurer.setLocations(new PathMatchingResourcePatternResolver().getResources("file:pathtToFile"));
configurer.setIgnoreUnresolvablePlaceholders(true);
return configurer;
}