老问题了java.lang.ClassCastException
HelloWorldServlet的代码
package com.servlet;

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

public class HelloWorldServlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("Hello World!!!");
}

}


web.xml的代码
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>servlet</display-name>

<servlet>
<servlet-name>HelloWorldServlet</servlet-name>
<servlet-class>com.servlet.HelloWorldServlet</servlet-class>
</servlet>

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


</web-app>



访问http://127.0.0.1:8080/servlet/HelloWorldServlet时候tomcat报错java.lang.ClassCastException：com.servlet.HelloWorldServlet cannot be cast to javax.servlet.Servlet

我看了些以前的帖子都说是类型转换错误，但是我里面没有类型转换 所以不解了 各路高人指点！

------解决方案--------------------
引错包了！