@ConfigurationProperties referencing properties that themselves reference other properties

Question

project.name=my-project
base.url=http://localhost:8080
cas.url=http://my-server:8010/cas
cas.callback.url=${base.url}/${project.name}

Basically I want to use the above in a spring-boot ConfigurationProperties but the casCallbackUrl is always null.

@Component
@ConfigurationProperties(prefix = "cas")
@Getter
@Setter
public class CasSettings {

    @NotBlank
    private String url; //this is resolved correctly

    @NotBlank
    private String callbackUrl; //callbackUrl is null

}

update

Well I got it working by camelCasing the property names, but according to the documentation you should be able to use dot notation for property names.

from:

cas.callback.url=${base.url}/${project.name}

to:

cas.callbackUrl=${base.url}/${project.name}

Why is spring-boot not picking up the dot notation?

Answer 1

The dot represents a separate object within the configuration properties object. cas.callback-url would work.

Answer 2

Spring relaxed property is not relaxed enugh to to transform dot notated properties to camel case fields. But you can implement it yourself easily:

@Service
@PropertySource("classpath:git.properties")
public class MngmntService implements EnvironmentAware {

    private BuildStatus buildStatus;
    private static final Logger LOG = LoggerFactory.getLogger(MngmntService.class);

    @Override
    public void setEnvironment(Environment env) {
        RelaxedPropertyResolver pr = new RelaxedPropertyResolver(env, "git.");
        buildStatus = new BuildStatus();
        for (Field field : BuildStatus.class.getDeclaredFields()) {
            String dotNotation = StringUtils.join(
                StringUtils.splitByCharacterTypeCamelCase(field.getName()),
                '.'
            );
            field.setAccessible(true);
            try {
                field.set(buildStatus, pr.getProperty(dotNotation, field.getType()));
            } catch (IllegalArgumentException | IllegalAccessException ex) {
                LOG.error("Error setting build property.", ex);
            }
        }
    }

    public BuildStatus getBuildStatus() {
        return buildStatus;
    }

Property object:

public class BuildStatus implements Serializable {

    private String tags;
    private String branch;
    private String dirty;

    private String commitId;
    private String commitIdAbbrev;
    private String commitTime;

    private String closestTagName;

    private String buildTime;
    private String buildHost;
    private String buildVersion;
    ...
}