Spring Boot: Use database and application.properties for configuration

Question

I need to save the configuration of the Spring Boot application in the database.

Is it possible to store the database information in the application.properties and use them to connect to the database and retrieve all the other properties from there?

So my application.properties would look like:

spring.datasource.url=jdbc:sqlserver://localhost:1433;databaseName=mydb
spring.datasource.username=user
spring.datasource.password=123456
spring.jpa.database-platform=org.hibernate.dialect.SQLServer2012Dialect

And the other configuration would be fetched from the database with something like this:

@Configuration
@PropertySource(value = {"classpath:application.properties"})
public class ConfigurationPropertySource {

    private final ConfigurationRepository configurationRepository;

    @Autowired
    public ConfigurationPropertySource(ConfigurationRepository configurationRepository) {
        this.configurationRepository = configurationRepository;
    }

    public String getValue(String key) {
        ApplicationConfiguration configuration = configurationRepository.findOne(key);
        return configuration.getValue();
    }

}

With ApplicationConfiguration as an Entity.

But Spring Boot does not get the configuration from the database.

Answer 1

I know that this an old question, but this post surely help someone like me who is struggling to find an exact solution.

We always love to write configurable code.

What if properties in database are available through @Value annotation ? Yes it is possible.

You just have to define a class which implements EnvironmentAware and add custom logic in setEnvironment method.

---

Let's start coding.

Define a database entity.

@Data
@Entity
@Builder
@NoArgsConstructor
@AllArgsConstructor
@Table(name = "app_config")
public class AppConfig {
    @Id
    private String configKey;

    private String configValue;
}

Define a JPA repository to fetch configurations from database.

@Repository
public interface AppConfigRepo extends JpaRepository<AppConfig, String> {
}

Below code will load database properties into application environment.

@Component("applicationConfigurations")
public class ApplicationConfigurations implements EnvironmentAware {

    @Autowired
    private AppConfigRepo appConfigRepo;

    @Override
    public void setEnvironment(Environment environment) {
        ConfigurableEnvironment configurableEnvironment = (ConfigurableEnvironment) environment;

        Map<String, Object> propertySource = new HashMap<>();
        appConfigRepo.findAll().stream().forEach(config -> propertySource.put(config.getConfigKey(), config.getConfigValue()));
        configurableEnvironment.getPropertySources().addAfter("systemEnvironment", new MapPropertySource("app-config", propertySource));
    }
}

We can add our database properties one level below system environment so that we can easily override without touching the database. Below code line helps us to achieve the same.

configurableEnvironment.getPropertySources().addAfter("systemEnvironment", new MapPropertySource("app-config", propertySource));

You have to add @DependsOn annotation on class where you want to use @Value annotation.

@DependsOn takes application configuration bean id as parameter so that our properties from database are loaded in environment before our custom beans load.

So, class will look like this

@Component
@DependsOn("applicationConfigurations")
public class SomeClass {

    @Value("${property.from.database}")
    private String property;

    // rest of the code
}

Please note, JPA configurations are added in application.properties.

Answer 2

One possible solution that you could workout, is to use ConfigurableEnvironment and reload and add properties.

@Configuration   
public class ConfigurationPropertySource {

private ConfigurableEnvironment env;

private final ConfigurationRepository configurationRepository;

    @Autowired
    public ConfigurationPropertySource(ConfigurationRepository configurationRepository) {
        this.configurationRepository = configurationRepository;
    }

    @Autowired
    public void setConfigurableEnvironment(ConfigurableEnvironment env) {

        this.env = env;
   }

   @PostConstruct
   public void init() {
    MutablePropertySources propertySources = env.getPropertySources();
       Map myMap = new HashMap();
       //from configurationRepository get values and fill mapp
       propertySources.addFirst(new MapPropertySource("MY_MAP", myMap));
   }

}