Creación dinámica de Spring Beans en tiempo de ejecución

La traducción ha sido preparada especialmente para futuros alumnos del curso "Developer on Spring Framework" .

Este artículo sobre binning dinámico se ha convertido en el más popular en mi blog en cinco años (más de 9.300 visitas). Es hora de actualizarlo. También agregué un ejemplo en Github .

: " Spring Bean , ". , . properties-.

1. , , :

package your.package;

@Retention(RetentionPolicy.RUNTIME)
public @interface InjectDynamicObject {
}

2. , :

@Service
public class CustomerServiceImpl {
    private Customer dynamicCustomerWithAspect;
    
    @InjectDynamicObject
    public Customer getDynamicCustomerWithAspect() {
        return this.dynamicCustomerWithAspect;
    }
}

3. Pointcut Advise, , 2:

@Component
@Aspect
public class DynamicObjectAspect {
    // This comes from the property file
    @Value("${dynamic.object.name}")
    private String object;
    @Autowired
    private ApplicationContext applicationContext;
    
    @Pointcut("execution(@com.lofi.springbean.dynamic.
        InjectDynamicObject * *(..))")
    public void beanAnnotatedWithInjectDynamicObject() {
    }
    @Around("beanAnnotatedWithInjectDynamicObject()")
    public Object adviceBeanAnnotatedWithInjectDynamicObject(
        ProceedingJoinPoint pjp) throws Throwable {   
        pjp.proceed();
        
        // Create the bean or object depends on the property file  
        Object createdObject = applicationContext.getBean(object);
        return createdObject;
    }
}

4. , @InjectDynamicObject. properties-. Customer: CustomerOneImpl CustomerTwoImpl:

@Component("customerOne")
public class CustomerOneImpl implements Customer {
    @Override
    public String getName() {
        return "Customer One";
    }
}

application.properties
dynamic.object.name=customerOne

5. :

@RunWith(SpringRunner.class)
@SpringBootTest
public class CustomerServiceImplTest {
    @Autowired
    private CustomerServiceImpl customerService;
    @Test
    public void testGetDynamicCustomerWithAspect() {
        // Dynamic object creation
        logger.info("Dynamic Customer with Aspect: " +
            customerService.getDynamicCustomerWithAspect()
            .getName());
}

, , . AspectJ, Spring. Map . eXTra Client. PluginsLocatorManager. Spring Map (String) .

"… Map , String. Map , — ".

. Spring.

@Service
public class CustomerServiceImpl {
    
    // We inject the customer implementations into a Map
    @Autowired
    private Map<String, Customer> dynamicCustomerWithMap;
    
    // This comes from the property file as a key for the Map
    @Value("${dynamic.object.name}")
    private String object;
    public Customer getDynamicCustomerWithMap() {
        return this.dynamicCustomerWithMap.get(object);
    }
}

" Spring Framework" .