component-scan get in the way of bean initialization? - spring

Question

I encounter this problem while I am trying to duplicate a simple spring OAuth project, sparklr2. source code here
https://github.com/spring-projects/spring-security-oauth/tree/master/samples/oauth2/sparklr
the source code runs perfectly, when I debug it with tomcat, it initialize all #Bean inside WebMvcConfigurerAdapter, including controllers. but noted that #ComponentScan() is not being used.
then I create my own MVC project, copy almost 100% of code, but I am using WebApplicationInitializer instead of AbstractDispatcherServletInitializer. I use WebApllicationInitializer because I have only learned this way to code MVC.
then I run the project, #Bean initialized. then I check /login with my browser, get 404. this could be caused by spring not knowing I have controllers, then I add #ComponentScan to my configuration class, /login now shows up.
but the weird thing is, all #Bean related to Controller, are not initialized. so, when I call any method to those controller, since their attributes are not initialized, gives me no object or null exception.
So, my point is, how does that sample works, I mean controller and jsp correctly handle and response without using #ComponentScan?
and look at it from different angle, why does #ComponentScan stop #Bean from being initialize in my project?
my WebApplicationInitializer
#Configuration
#EnableWebMvc
#ComponentScan("umedia.test.oauth.controller")
public class MvcConfig extends WebMvcConfigurerAdapter {
#Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
#Bean
public ContentNegotiatingViewResolver contentViewResolver()
throws Exception {
ContentNegotiationManagerFactoryBean contentNegotiationManager = new ContentNegotiationManagerFactoryBean();
contentNegotiationManager.addMediaType("json",
MediaType.APPLICATION_JSON);
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setViewClass(JstlView.class);
viewResolver.setPrefix("/WEB-INF/views/");
viewResolver.setSuffix(".jsp");
MappingJackson2JsonView defaultView = new MappingJackson2JsonView();
defaultView.setExtractValueFromSingleKeyModel(true);
ContentNegotiatingViewResolver contentViewResolver = new ContentNegotiatingViewResolver();
contentViewResolver
.setContentNegotiationManager(contentNegotiationManager
.getObject());
contentViewResolver.setViewResolvers(Arrays
.<ViewResolver> asList(viewResolver));
contentViewResolver.setDefaultViews(Arrays.<View> asList(defaultView));
return contentViewResolver;
}
#Bean
public PhotoServiceImpl photoServices() {
List<PhotoInfo> photos = new ArrayList<PhotoInfo>();
photos.add(createPhoto("1", "marissa"));
photos.add(createPhoto("2", "paul"));
photos.add(createPhoto("3", "marissa"));
photos.add(createPhoto("4", "paul"));
photos.add(createPhoto("5", "marissa"));
photos.add(createPhoto("6", "paul"));
PhotoServiceImpl photoServices = new PhotoServiceImpl();
photoServices.setPhotos(photos);
return photoServices;
}
// N.B. the #Qualifier here should not be necessary (gh-298) but lots of
// users report needing it.
#Bean
public AdminController adminController(
TokenStore tokenStore,
#Qualifier("consumerTokenServices") ConsumerTokenServices tokenServices,
SparklrUserApprovalHandler userApprovalHandler) {
AdminController adminController = new AdminController();
adminController.setTokenStore(tokenStore);
adminController.setTokenServices(tokenServices);
adminController.setUserApprovalHandler(userApprovalHandler);
return adminController;
}
// this url, do I need to change it?
private PhotoInfo createPhoto(String id, String userId) {
PhotoInfo photo = new PhotoInfo();
photo.setId(id);
photo.setName("photo" + id + ".jpg");
photo.setUserId(userId);
photo.setResourceURL("/org/springframework/security/oauth/examples/sparklr/impl/resources/"
+ photo.getName());
return photo;
}
#Override
public void configureDefaultServletHandling(
DefaultServletHandlerConfigurer configurer) {
configurer.enable();
}
#Bean
public PhotoServiceUserController photoServiceUserController(
PhotoService photoService) {
PhotoServiceUserController photoServiceUserController = new PhotoServiceUserController();
return photoServiceUserController;
}
#Bean
public PhotoController photoController(PhotoService photoService) {
PhotoController photoController = new PhotoController();
photoController.setPhotoService(photoService);
return photoController;
}
#Bean
public AccessConfirmationController accessConfirmationController(
ClientDetailsService clientDetailsService,
ApprovalStore approvalStore) {
AccessConfirmationController accessConfirmationController = new AccessConfirmationController();
accessConfirmationController
.setClientDetailsService(clientDetailsService);
accessConfirmationController.setApprovalStore(approvalStore);
return accessConfirmationController;
}
/* #Bean
public ViewResolver viewResolver() {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setViewClass(JstlView.class);
viewResolver.setPrefix("/WEB-INF/views/");
viewResolver.setSuffix(".jsp");
return viewResolver;
}*/
#Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/resources/**").addResourceLocations(
"/resources/");
}
}

Answer 1

so, you have #ComponentScan which interacts with #Controller on your controllers + still create #Bean's with those?
As a first step try to remove #Beans and try to inject dependencies using #Autowired on controllers' constructors. Then #ComponentScan should recognize #Controller, inject dependencies and use #RequestMapping without issues.