CODEWITHSUNDEEP
javaconfigurationspring-boot
Michaël Técourt
Michaël Técourt

Reputation: 3527

Spring Boot @ConfigurationProperties correct usage

We are actually using Spring Boot's @ConfigurationProperties as basically a configuration mapper : it provides us an easy shortcut to map properties on objects.

@ConfigurationProperties("my.service")
public class MyService {
    private String filePrefix;
    private Boolean coefficient;
    private Date beginDate;
    // getters/setters mandatory at the time of writing

    public void doBusinessStuff() {
        // ...
    }
}

Although this was a nice productivity boost when we were prototyping the app, we came to question if this was right usage.

I mean, configuration properties have a different status in Spring Boot's context, they're exposed through actuator endpoints, they can be used to trigger conditional beans, and seem more oriented toward technical configuration properties.

Question : Is it "correct" to use this mechanism on any business property/value, or is it plain misuse ?

Any potential drawback we missed ?

Right now our only concern is that we cannot use @ConfigurationProperties on immutable classes, which is closely related to this issue on Spring Boot's tracker : Allow field based @ConfigurationProperties binding

Upvotes: 0

Views: 2051

Answers (1)

jst
jst

Reputation: 1757

If your property represents something that is configurable based on the environment/profile that is what the mechanism is there for. Though I'm a little unclear what you mean by "map properities on objects".

I would not favor this style in general, especially if your bean has multiple properties to set. A more standard idiom is to have a class that encapsulates the properties/settings used to create your bean:

@ConfigurationProperties("my.service")
public class MyServiceProperties {
    private String filePrefix;
    private Boolean coefficient;
    private Date beginDate;
    // getters/setters mandatory at the time of writing   
}

then your Service class would look like this:

@EnableConfigurationProperties(MyServiceProperties.class)
public class MyService {
    @Autowired
    private MyServiceProperties properties;
    //do stuff with properties

    public void doBusinessStuff() {
        // ...
    }
}

This would at least allow you to pass the properties easily into an immutable class through it's constructor (make copies of any mutable properties). Also having the properties bean can be reused if you find other parts of your app need some shared configuration.

Upvotes: 1

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