Spring @Inject服务类返回空指针异常

Question

I have a Converter class where I have used the following so that I can use @Inject to access my service class.

@Named("myMB")
@ViewAccessScoped

However when I tried to use

myservice.getCategories();

I am getting null pointer exception at this line. What could be the reason for this? I have used the same service method in ManagedBean to populate selectOneMenu , but when used in Converter class, gives me exception.

Converter class

@FacesConverter("categoryConverter")
@Named("myMB")
@ViewAccessScoped
public class CategoryConverter implements Converter {

@Inject
CategoryService myservice;

    @Override
        public Object getAsObject(FacesContext facesContext, UIComponent component,
                String value) {
            System.out.println("reached in converter "+value);
            try {


                    List<Category> cat = myservice.getCategories();
                    for (Category cat : category) {
                        if (cat.getCategoryCode() == value) {
                            return cat;
                        }
                    }
                }

            } catch (Exception e) {
                System.out.println("exception from getAsObject  ");
                e.printStackTrace();
            }
            return null;
        }

Answer 1

That can happen if you used it as @FacesConverter instance instead of as @Named instance. The @Inject doesn't work on @FacesConverter . Get rid of @FacesConverter to avoid future confusion and reference the converter as converter="#{categoryConverter}" (which uses @Named ) instead of as converter="categoryConverter" (which uses @FacesConverter ).

Note that I assume that the Spring part is properly configured, otherwise it would be still null . I don't do Spring, so I can't tell form top of head if it works inside a CDI managed bean instead of a Spring managed bean. I find it only surprising and amusing that you're mixing CDI and Spring, while Spring is intented as competitor/alternative to CDI/EJB.