Spring MVC - DispatcherServlet by annotations

Question

I got spring MVC application. It runs on Tomcat 7. By now i got this part in my web.xml file:

<servlet>
        <servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>
                /WEB-INF/app-config.xml
            </param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
        <url-pattern>*.htm</url-pattern>
    </servlet-mapping>

Is there any way to init it by annotations? I got a MainSettings.java class where all my beans are initialyzed by @Bean annotation. So how do i initDispatherServlet there?

Solution 1

Here is the example with comments. Hope this helps you.

public class ApplicationInitializer implements WebApplicationInitializer {

    //Called first when the application starts loading.
    public void onStartup(ServletContext servletContext)
            throws ServletException {
        System.out.println("Inside application initializer...");

        //Registering the class that incorporates the annotated DispatcherServlet configuration of spring
        AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
        rootContext.register(DispatcherConfig.class);

        //Adding the listener for the rootContext
        servletContext.addListener(new ContextLoaderListener(rootContext));

        //Registering the dispatcher servlet mappings.
        ServletRegistration.Dynamic dispatcher = servletContext.addServlet("dispatcher", new DispatcherServlet(rootContext));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("/");
    }

}

Solution 2

Writing this because Japs's answer leads to creation of another context, which doesn't see the contents of the security context.

public class WebInitializer extends
        AbstractAnnotationConfigDispatcherServletInitializer {

    private static final Log LOGGER = LogFactory.getLog(WebInitializer.class);

    @Override
    protected Class<?>[] getRootConfigClasses() {
        /*  this is where you will return you config class
         *  your root config class should @Import other configs 
         *  to make them work without needing them to add there
         */
        return new Class[] { ViewConfig.class };
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[0];
    }

    @Override
    protected String[] getServletMappings() {
        return new String[] { "/" };
    }

}

Comments

[M. Deinum]

You don't want to pass your rootContext to the DispatcherServlet. Pass it an empty context that has the rootContext as the parent. Else the context will be initialized twice. I would also suggest extending the AbstractAnnotationConfigDispatcherServletInitializer instead of implementing the WebApplicationInitializer.

[Shervin Asgari]

I can't find DispatcherConfig.class. Where can I get this from?

[Japan Trivedi]

@ShervinAsgari Check your Sprint-mvc dependencies. Make sure you have correct version. Above example is based on Spring 3.2

[Cameron Hudson]

@ShervinAsgari It's user-defined. docs.spring.io/spring/docs/current/javadoc-api/org/…