Spring Boot アプリを properties と profile でどう設定するのか?

@Component
public class SearchService {
    // Inject a single property; :20 is the fallback if it is missing.
    @Value("${app.page-size:20}")
    private int pageSize;
}

@Component
@ConfigurationProperties(prefix = "app") // binds app.* into these fields
public class AppProps {
    private int pageSize;
    private Map<String, Boolean> featureFlags;
    // getters/setters — Boot relaxed-binds page-size -> pageSize
}

spring:
  config:
    activate:
      on-profile: prod       # only when 'prod' is active
server:
  port: 80