怎么出现异常？

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
        version="4.0">

   <servlet>
       <servlet-name>indexServlet</servlet-name>
       <servlet-class>com.zyh.servlet.IndexServlet</servlet-class>
   </servlet>

   <servlet-mapping>
       <servlet-name>indexServlet</servlet-name>
       <url-pattern>/indexServlet</url-pattern>
   </servlet-mapping>

   <servlet>
       <servlet-name>importExcelInitServlet</servlet-name>
       <servlet-class>com.zyh.servlet.ImportExcelInitServlet</servlet-class>
   </servlet>

   <servlet-mapping>
       <servlet-name>importExcelInitServlet</servlet-name>
       <url-pattern>/importExcelInit</url-pattern>
   </servlet-mapping>


</web-app>

package com.zyh.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class ImportExcelInitServlet extends HttpServlet {

   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       this.doPost(req, resp);
   }

   @Override
   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       request.getRequestDispatcher("/WEB-INF/views/importExcel.jsp").forward(request, response);
   }
}