스프링 구성 정보

public class Client {
	public static void main(String[] args) {
    	BeanFactory beanFactory = new AnnotationConfigApplicationContext(ObjectFactory.class);
        PaymentService paymentService = beanFactory.getBean(PaymentService.class);
        
        Payment payment = paymentService.prepare(...);
        ...
    }
}

@Configuration
@ComponentScan
public class ObjectFactory {
/*
	@Bean
    public PaymentService paymentService() {
    	return new PaymentService(exRateProvider());
    }
    
    @Bean
    public ExRateProvider exRateProvider() {
    	return new SimpleRateProvider();
    }
*/
}

@Component
public class PaymentService {
	private final ExRateProvider exRateProvider;
    public PaymentService(ExRateProvider exRateProvider) {
    	this.exRateProvider = exRateProvider;
    }
    ...
}

@Component
public class SimpleRateProvider implements ExRateProvider {
    ...
}