Spring boot web - Autowire bean into an XML defined bean is null

Question

I am converting my existing Spring 3.1 based web application into Spring Boot 1.2.5. I initially upgraded my old application to Spring 4.1.7.

The old application has many xml bean configuration files imported using init parameter contextConfigLocation in the web.xml . In the new Spring boot application these xml are imported using @ImportResource in the main class.

When I start my application, I could see that the xml based beans are created with autowired fields null . When I debug the bean creation part, it looks like the AutowiredAnnotationBeanPostProcessor is not yet added to the beanfactory. But xml contains <context:annotation-config /> , which suppose to add the AutowiredAnnotationBeanPostProcessor . Also this post processor getting added right after my xml based beans are created.

Many of the bean dependencies are autowired bean in the xml defined bean.

sample xml config:

<context:annotation-config/>
<context:component-scan base-package="x.y.z"/>
<bean id="discoveredResourceClasses" factory-bean="resourceManager" factory-method="getResourceClasses">
    <constructor-arg>
        <list>
            <value>x.y.z.resources</value>
        </list>
    </constructor-arg>
</bean>

Factotry Bean class which is used to create 'discoveredResourceClasses' bean:

@Service
public class ResourceManager implements Serializable{
    @Autowired
    protected IExtensionManager extensionManager;

    public List<Class<? extends Resource>> getResourceClasses(String ... packageNames)
    {
        return extensionManager.getExtensions(packageName, includeEverything, Resource.class);
    }
}

Autowired bean:

@Service
public class ExtensionManager implements IExtensionManager {

    public <T> List<T> getExtensions(String packageName, Map<String, String> filter, Class<T> clazz) {
        //busoinesslogic .
    }

}

Spring boot class :

@ImportResource("classpath*:xad-config-all.xml")
@SpringBootApplication
public class Application extends SpringBootServletInitializer {

   @Override
   protected SpringApplicationBuilder configure(SpringApplicationBuilder              application) {
    return application.sources(Application.class);
   }

   public static void main(String[] args) {
      SpringApplication.run(Application.class, args);
   }

}

At the time of resourceManager bean creation, the field extensionManager is coming as null . So the factory-method(getResourceClasses) throws NullPointerException .

Answer 1

You need to provide path to the xml configuration file at the beggining, when Spring didn't started building application context. The @ImportResource annotation are processed in the middle of this process, after many of PostProcessors have been registered.

You need to provide a path to the xml configuration using SpringApplicationBuilder.sources method.

@SpringBootApplication
public class Application extends SpringBootServletInitializer {

@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
    return builder.sources("classpath:/WEB-INF/context/payables-profile.xml", Application.class);
}