In Springboot, how to serialize properties into objects when using @ConfigurationProperties and @PropertySource?

Question

When using @ConfigurationProperties with @PropertySource(value = "myconfig.yml") Springboot doesn't serialize my properties into an object

If I put this same config in application.yml and remove the @PropertySource(value = "myconfig.yml"), then it works

---
testPrefix.simpleProperty: my.property.haha
testPrefix.complexProperties:
  -
    firstName: 'Clark'
    lastName: 'Ken'
  -
    firstName: 'Roger'
    lastName: 'Federer'

@Configuration
@ConfigurationProperties(prefix = "testPrefix")
@PropertySource(value = "testConfigFile.yml")
public class MyTestProperties {
  private String simpleProperty;
  private List<Person> complexProperties;

getters

setters

@SpringBootApplication
public class App implements CommandLineRunner {

  MyTestProperties myProperties;

  @Autowired
  public App(MyTestProperties properties) {
    this.properties = properties;
  }

  public static void main(String[] args) {
    SpringApplication app = new SpringApplication((App.class));
    app.run(args);
  }

  @Override
  public void run(String... args) throws Exception {
    System.out.println(myProperties.getSimpleProperty()); 
    myProperties.getComplexProperties.stream.forEach(System.out::println));
  }
}

Output:

my.property.haha

Answer 1

To my knowledge, YAML properties cannot be loaded using a @PropertySource . I'll look it up as I'm not sure whether the issue has been resolved in the meantime.

[edit] Apparently, it hasn't been fixed:

YAML files cannot be loaded by using the @PropertySource annotation. So, in the case that you need to load values that way, you need to use a properties file.

Answer 2

You need to use jackson yaml dependency.

//pom.xml
<dependency>
  <groupId>com.fasterxml.jackson.dataformat</groupId>
  <artifactId>jackson-dataformat-yaml</artifactId>
</dependency>

Then create a factory class for loading yaml files as property sources.

//YamlPropertySourceFactory.java

import java.io.IOException;

import org.springframework.beans.factory.config.YamlPropertiesFactoryBean;
import org.springframework.core.env.PropertiesPropertySource;
import org.springframework.core.env.PropertySource;
import org.springframework.core.io.support.EncodedResource;
import org.springframework.core.io.support.PropertySourceFactory;

public class YamlPropertySourceFactory implements PropertySourceFactory {

    @Override
    public PropertySource<?> createPropertySource(String s,
            EncodedResource encodedResource) throws IOException {
        YamlPropertiesFactoryBean bean = new YamlPropertiesFactoryBean();
        bean.setResources(encodedResource.getResource());
        return new PropertiesPropertySource(
                s != null ? s : encodedResource.getResource().getFilename(),
                bean.getObject());
    }

}

Then use PropertySource annotation like this.

@PropertySource(factory = YamlPropertySourceFactory.class, value = "testConfigFile.yml")
public class MyTestProperties {
  private String simpleProperty;
  private List<Person> complexProperties;