运行show.jsp报404什么情况？

package com.demo.sm.globe;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import javax.servlet.GenericServlet;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class DispatcherServlet extends GenericServlet {

   private ApplicationContext context;

   public void init() throws ServletException {
       super.init();
       context = new ClassPathXmlApplicationContext("spring.xml");
   }

   public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
       HttpServletRequest request = (HttpServletRequest) servletRequest;
       HttpServletResponse response = (HttpServletResponse) servletResponse;

       /*
              staff/add.do        login.do
              staffController
              public void add(HttpServletRequest request, HttpServletResponse response){}
       *
        */
       String path = request.getServletPath().substring(1);
       String beanName = null;
       String methodName = null;
       int index = path.indexOf('/');
       if (index != -1) {
           beanName = path.substring(0, index) + "Controller";
           methodName = path.substring(index + 1, path.indexOf(".do"));
       } else {
           beanName = "selfController";
           methodName = path.substring(0, path.indexOf(".do"));
       }

       Object obj = context.getBean(beanName);
       try {
           Method method = obj.getClass().getMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);
           method.invoke(obj,request,response);
       } catch (NoSuchMethodException e) {
           e.printStackTrace();
       } catch (IllegalAccessException e) {
           e.printStackTrace();
       } catch (InvocationTargetException e) {
           e.printStackTrace();
       }
   }
}