tomcat启动java web项目为什么抛出异常：java.lang.ClassNotFoundException: org.springframework.web.filter.CharacterEncodingFilter?

严重: Exception starting filter encoding

java.lang.ClassNotFoundException: org.springframework.web.filter.CharacterEncodingFilter

tomcat可以启动

我的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

 <servlet>
  <servlet-name>springMvc</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springMvc.xml</param-value>
  </init-param>
 </servlet>
 <servlet-mapping>
  <servlet-name>springMvc</servlet-name>
  <url-pattern>*.do</url-pattern>
 </servlet-mapping>
   <filter>
   <filter-name>encoding</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>
 </filter> 
 <filter-mapping>
   <filter-name>encoding</filter-name>
   <url-pattern>/*</url-pattern>
 </filter-mapping>
 <welcome-file-list>
  <welcome-file>login.jsp</welcome-file>
 </welcome-file-list>
 <login-config>
  <auth-method>BASIC</auth-method>
 </login-config>
</web-app>