Can Spring Boot Use Both YAML and Properties Files Simultaneously?

Can I configure my Spring Boot application to use both YAML and properties files at the same time?

Yes, Spring Boot supports using both YAML (.yml) files and properties (.properties) files simultaneously. This allows you to leverage the user-friendly structure of YAML while maintaining compatibility with components that require properties files.

application.yml
---
server:
  port: 8080
logging:
  level:
    root: INFO

application-dev.properties
---
server.port=8081
logging.level.root=DEBUG

public class Application { // Main class
    public static void main(String[] args) { // Entry point
        SpringApplication.run(Application.class, args);
    }
}

Causes

• Flexibility of YAML for complex structures.
• Internal components require properties for specific configurations.

Solutions

• Create your application.yml file for general configurations.
• Create an application-${profile}.properties file for environment-specific settings.
• Spring Boot automatically merges both files, giving precedence to properties files if there’s a conflict.

Mistake: Forgetting to name the properties file correctly (application-${profile}.properties).

Solution: Ensure that the naming convention of the properties file matches the active profile.

Mistake: Assuming YAML and properties files cannot coexist.

Solution: Spring Boot supports both formats, so you can use them together without issues.

Mistake: Not setting the correct order of precedence.

Solution: Know that Spring Boot favors properties files over YAML files for overlapping keys.