eclipse运行tomcat项目报错错误如下：

十二月 27, 2013 10:24:38 上午 org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Allocate exception for servlet dispatcherServlet
java.lang.ClassNotFoundException: org.apache.commons.dbcp.BasicDataSource
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
at org.springframework.util.ClassUtils.forName(ClassUtils.java:257)
at org.springframework.beans.factory.support.AbstractBeanDefinition.resolveBeanClass(AbstractBeanDefinition.java:321)
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1058)
at org.springframework.beans.factory.support.AbstractBeanFactory.isBeanClassMatch(AbstractBeanFactory.java:1086)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:173)
at org.springframework.context.support.AbstractApplicationContext.getBeanNamesForType(AbstractApplicationContext.java:736)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:403)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:334)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:311)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:258
。。。。。。。。