Caused by: java.lang.NoClassDefFoundError: javax/faces/webapp/FacesServlet

1、错误描述

严重: Exception starting Context with name [/DoJo]
org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/DoJo]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
	at org.apache.catalina.core.StandardContext.reload(StandardContext.java:4009)
	at org.apache.catalina.startup.HostConfig.reload(HostConfig.java:1479)
	at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1462)
	at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1646)
	at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:328)
	at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
	at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
	at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1374)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1546)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1556)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1524)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NoClassDefFoundError: javax/faces/webapp/FacesServlet
	at com.sun.faces.config.FacesInitializer.<clinit>(FacesInitializer.java:103)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:270)
	at org.apache.catalina.startup.WebappServiceLoader.loadServices(WebappServiceLoader.java:187)
	at org.apache.catalina.startup.WebappServiceLoader.load(WebappServiceLoader.java:152)
	at org.apache.catalina.startup.ContextConfig.processServletContainerInitializers(ContextConfig.java:1559)
	at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1281)
	at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:889)
	at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:386)
	at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
	at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5380)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	... 12 more
Caused by: java.lang.ClassNotFoundException: javax.faces.webapp.FacesServlet
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
	... 25 more

2、错误原因

      DoJo是一个Java Web项目，部署到Tomcat后，由于要部署另外一个项目，我到D:\MyEclipse10\apache-tomcat-7.0.57\webapps目录删除DoJo，但MyEclipse10控制台出现这个错误

3、解决办法