Spring mvc 当我使用SpringMVC运行我的简单Web应用程序时，localhost上的TomcatV8.5服务器无法启动

我有一个非常简单的SpringMVCwebapp和maven。但是我不知道为什么我的WebInitializer有NullPointerException

当我在WebInitailizer类中设置断点时，我发现dispatcher变量为null。但我不知道为什么？ 我错过什么了吗？ 谢谢

这是我的WebInitializer类：

@Configuration
public class WebInitializer implements WebApplicationInitializer{
    
    @Override
    public void onStartup(ServletContext container) throws ServletException {
        AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
        ctx.register(SpringConfiguration.class);
        
        ctx.setServletContext(container);
        
        ServletRegistration.Dynamic dispatcher = container.addServlet("dispatcher", new DispatcherServlet(ctx));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("/");
         
        //Áp dụng encodingfileter cho project 
        CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter("UTF-8", true);
        container.addFilter("encodingFilter", characterEncodingFilter)
        .addMappingForUrlPatterns(null, false, "/*");
        
    }
}

这是我在控制台中收到的错误

Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/SpringBanHang]]
    at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:122)
    at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:191)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:931)
    ... 8 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/SpringBanHang]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    ... 6 more
Caused by: java.lang.NullPointerException
    at com.banhang.configuration.WebInitializer.onStartup(WebInitializer.java:24)
    at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:169)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5154)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 6 more