Basic properties handling - Part 3

16.03.2018 by Jens in Spring Boot | Newsletter

Using @Value to inject properties is fine as long as it is just a handful. When we have more, and they are grouped around a single configuration entity like all props for a remote connection, we can introduce a configuration class using the @ConfigurationProperties annotation of Spring Boot.

We can mark a simple POJO with it and Spring Boot map properties to fields of the class.

@ConfigurationProperties("cb")
public class CBProperties {

    private boolean enabled;

    private int timeout;

    private String host;

    // standard getters and setters
}

The parameter @ConfigurationProperties accepts, is the prefix for our properties. The keys of the example above look like:

• cb.enabled
• cb.timeout

We can inject this class like any other Spring Bean.

However, before we can use this feature, we must enable it on one of our @Confiuration classes by adding the @EnableConfigurationProperties annotation and give it the name of our config property class like:

@Configuration
@EnableConfigurationProperties(CBProperties.class)
public class MyConfiguration {
}

Voila!

Nice, isn’t it? And it even supports nested classes.