tomcat修改了context doc-base为项目里面的文件夹后项目的servlet找不到

我的项目名称叫drivproj，里面有个文件夹叫offsite，我在tomcat的server.xml里将context doc-base修改为drivproj/offsite，那么我原先在drivproj/web-inf里的web.xml里添加的servlet就不起作用了！运行当用到servlet的时候提示找不到该名称！
求大神帮忙！急急急！
另附WEB.XML:
<?xml version="1.0" encoding="utf-8"?>

<!DOCTYPE web-app

PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"

"http://java.sun.com/dtd/web-app_2_3.dtd">

<display-name>My Web Application</display-name>

<description>A application for driver.</description>

<context-param>

    <param-name>contextConfigLocation</param-name>

    <param-value>classpath:/spring/*.xml</param-value>
    <!--

    -->
</context-param>

<listener>

    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

</listener>

<servlet>

    <servlet-name>spring-mvc</servlet-name>

    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

    <init-param>

        <param-name>contextConfigLocation</param-name>

        <param-value>classpath:/spring/springmvc-servlet.xml</param-value>

    </init-param>

    <load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

    <servlet-name>spring-mvc</servlet-name>

    <url-pattern>*.json</url-pattern>

</servlet-mapping>
<servlet>
    <servlet-name>sponsor</servlet-name>
    <servlet-class>com.news.Sponsorsendmail</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>sponsor</servlet-name>
    <url-pattern>/sponsor</url-pattern>
</servlet-mapping>

<!--编码过滤器-->  

<filter>  

    <filter-name>encodingFilter</filter-name>  

    <filter-class>  

        org.springframework.web.filter.CharacterEncodingFilter  

    </filter-class>  

    <init-param>  

        <param-name>encoding</param-name>  

        <param-value>UTF-8</param-value>  

    </init-param>  

    <init-param>  

        <param-name>forceEncoding</param-name>  

        <param-value>false</param-value>  

    </init-param>  

</filter>  

<filter-mapping>  

    <filter-name>encodingFilter</filter-name>  

    <url-pattern>/*</url-pattern>  

</filter-mapping> 

<welcome-file-list>

    <welcome-file>index.html</welcome-file>

</welcome-file-list>