Servlet 3.0没有web.xml错误-页面javaconfig

import javax.servlet.ServletContainerInitializer;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.HandlesTypes;
import javax.servlet.annotation.WebListener;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;

@WebListener
@HandlesTypes({MyServlet.class})
public class MyServletContainerInitializer implements ServletContainerInitializer {

    @Override
    public void onStartup(Set<Class<?>> c, ServletContext ctx) throws ServletException {
        for (Class<?> clazz : c) {
            if (clazz.isAnnotationPresent(WebServlet.class)) {
                WebServlet annotation = clazz.getAnnotation(WebServlet.class);
                String[] urlPatterns = annotation.urlPatterns();
                HttpServlet servlet;
                try {
                    servlet = (HttpServlet) clazz.newInstance();
                    for (String urlPattern : urlPatterns) {
                        ctx.addServlet(clazz.getSimpleName(), servlet).addMapping(urlPattern);
                    }
                } catch (InstantiationException | IllegalAccessException e) {
                    throw new ServletException(e);
                }
            }
        }
    }
}