@Autowired in ServletContextListener

Question

i hava aclass InitApp

@Component
public class InitApp implements ServletContextListener {

@Autowired
ConfigrationService weatherConfService;

/** Creates a new          


        

Answer 1

A couple of ideas came to me as I was having the same issue.

First one is to use Spring utils to retrieve the bean from the Spring context within the listener:

Ex:

@WebListener
public class CacheInitializationListener implements ServletContextListener {

    /**
     * Initialize the Cache Manager once the application has started
     */
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        CacheManager cacheManager = WebApplicationContextUtils.getRequiredWebApplicationContext(
                sce.getServletContext()).getBean(CacheManager.class);
        try {
            cacheManager.init();
        } catch (Exception e) {
            // rethrow as a runtime exception
            throw new IllegalStateException(e);
        }
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        // TODO Auto-generated method stub

    }
}

This works fine if you only have one or two beans. Otherwise it can get tedious. The other option is to explicitly call upon Spring's Autowire utilities:

@WebListener
public class CacheInitializationListener implements ServletContextListener {

    @Autowired
    private CacheManager cacheManager;

    /**
     * Initialize the Cache once the application has started
     */
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);
        try {
            cacheManager.init();
        } catch (Exception e) {
            // rethrow as a runtime exception
            throw new IllegalStateException(e);
        }
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        // TODO Auto-generated method stub

    }
}

The caveat in both these solutions, is that the Spring context must by loaded first before either of these can work. Given that there is no way to define the Listener order using @WebListener, ensure that the Spring ContextLoaderListener is defined in web.xml to force it to be loaded first (listeners defined in the web descriptor are loaded prior to those defined by annotation).