Spring multiple @ConfigurationProperties with same class

Question

I have a class of the sort :

@Data
@Component
@ConfigurationProperties("a.config.props")
public class ClientProperties {

    private String hostname;
    private String port;
    private String baseUrl;
    private String endpoint;
}

I have tens of property contexts but for 1 line i have to repeat the whole class. Is there a simple and elegant way to have one class and somehow pass the property context dynamically (maybe an array or something of the sort) so that i use the same class.

Answer 1

You can just have a single class that describes your numerous & identical property blocks;

@Data
public class ClientProperties {
    private String hostname;
    private String port;
    private String baseUrl;
    private String endpoint;
}

Then refer to it as such to link that single class with different property blocks;

@Configuration
public class PropertyConfigurer {

    @Bean
    @ConfigurationProperties("props.one")
    private ClientProperties propsOne() {
        return new ClientProperties();
    }

    @Bean
    @ConfigurationProperties("props.two")
    private ClientProperties propsTwo() {
        return new ClientProperties();
    }

    @Bean
    @ConfigurationProperties("props.three")
    private ClientProperties propsThree() {
        return new ClientProperties();
    }
}

Then you can access them via their method names as qualifiers;

@Component
public class SomeService {

    @Autowired
    private ClientProperties propsOne;
    @Autowired
    private ClientProperties propsTwo;
    @Autowired
    private ClientProperties propsThree;

    ... some logic
}

Answer 2

I would suggest to create an abstract class with all the properties and extend the abstract class for as many property variants you have.

@Data
public abstract class BaseClientProperties {
    private String hostname;
    private String port;
    private String baseUrl;
    private String endpoint;
}

@Configuration
@ConfigurationProperties("a.config.props1")
public class Client1Properties extends BaseClientProperties{

}

@Configuration
@ConfigurationProperties("a.config.props2")
public class Client2Properties extends BaseClientProperties{
}

Use them as below:

@Service
public class SomeService {

    @Autowired
    private Client1Properties client1Properties;
    @Autowired
    private Client2Properties client2Properties;

    ... service logic
}