Java Servlet - ServletRegistration.Dynamic Examples

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletRegistration;
import javax.servlet.annotation.WebListener;
import java.util.Locale;

@WebListener
public class AppContextListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent event) {
        Locale locale = Locale.getDefault();
        ServletRegistration.Dynamic registration = event.getServletContext()
                .addServlet("appController", locale.getISO3Country().equals("USA") ?
                        DefaultAppController.class : OffshoreAppController.class);
        registration.addMapping("/app/");

    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {

    }
}

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;


public class MyWebInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup (ServletContext servletContext) throws ServletException {
        AnnotationConfigWebApplicationContext ctx =
                            new AnnotationConfigWebApplicationContext();
        //register our config class
        ctx.register(MyWebConfig.class);

        ctx.setServletContext(servletContext);

        //using servlet 3 api to dynamically create
        //spring dispatcher servlet
        ServletRegistration.Dynamic servlet =
                            servletContext.addServlet("springDispatcherServlet",
                                                      new DispatcherServlet(ctx));

        servlet.setLoadOnStartup(1);
        servlet.addMapping("/");
    }
}