Guide to @EnableConfigurationProperties

1. Introduction

In this quick tutorial, we’ll show how to use an @EnableConfigurationProperties annotation with @ConfigurationProperties annotated classes.

2. Purpose of @EnableConfigurationProperties Annotation

@EnableConfigurationProperties annotation is strictly connected to @ConfiguratonProperties.

It enables support for @ConfigurationProperties annotated classes in our application. However, it’s worth to point out that the Spring Boot documentation says, every project automatically includes @EnableConfigurationProperties. Therefore, @ConfiguratonProperties support is implicitly turned on in every Spring Boot application.

In order to use a configuration class in our project, we need to register it as a regular Spring bean.

First of all, we can annotate such class with @Component. Alternatively, we can use a @Bean factory method.

However, in certain situations, we may prefer to keep a @ConfigurationProperties class as a simple POJO. This is when @EnableConfigurationProperties comes in handy. We can specify all configuration beans directly on this annotation.

This is a convenient way to quickly register @ConfigurationProperties annotated beans.

3. Using @EnableConfigurationProperties

Now, let’s see how to use @EnableConfigurationProperties in practice.

First, we need to define our example configuration class:

@ConfigurationProperties(prefix = "additional")
public class AdditionalProperties {

    private String unit;
    private int max;

    // standard getters and setters
}

Note that we annotated the AdditionalProperties only with @ConfigurationProperties. It’s still a simple POJO!

Finally, let’s register our configuration bean using @EnableConfigurationProperties:

@Configuration
@EnableConfigurationProperties(AdditionalProperties.class)
public class AdditionalConfiguration {
    
    @Autowired
    private AdditionalProperties additionalProperties;
    
    // make use of the bound properties
}

That’s all! We can now use AdditionalProperties like any other Spring bean.

4. Conclusion

In this quick tutorial, we presented a convenient way to quickly register a @ConfigurationProperties annotated class in Spring.

As usual, all the examples used in this article are available over on GitHub.

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