Unable to autowire the service inside my authentication filter in Spring

Question

I am trying to authenticate user by token, But when i try to auto wire one my services inside the AuthenticationTokenProcessingFilter i get null pointer excepti

Answer 1

I am late to the party but this solution worked for me.

Add a ContextLoaderListener in web.xml. applicationContext can have dependency beans.

    org.springframework.web.context.ContextLoaderListener


    contextConfigLocation
    /WEB-INF/applicationContext.xml

Then add in MyFilter SpringBeanAutowiringSupport processInjectionBasedOnServletContext which will add the webapplicationcontext into the filter which will add all the dependencies.

@Component
public class MyFilter implements Filter {

    @Autowired
    @Qualifier("userSessionServiceImpl")
    private UserSessionService userSessionServiceImpl;

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain 
    chain) throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest) req;
        if (userSessionServiceImpl == null) {
            ServletContext context = httpRequest.getSession().getServletContext();
        SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this, context);
    }

       .... (for brevity)
    }

}