A child container failed during start

<pre name="code" class="java">严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]
	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
	at java.util.concurrent.FutureTask.get(FutureTask.java:188)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1122)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:819)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1574)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1564)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
	... 6 more
Caused by: java.lang.NoClassDefFoundError: SessionFactory
	at java.lang.Class.getDeclaredMethods0(Native Method)
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2570)
	at java.lang.Class.getDeclaredMethods(Class.java:1855)
	at org.apache.catalina.util.Introspection.getDeclaredMethods(Introspection.java:127)
	at org.apache.catalina.startup.WebAnnotationSet.loadMethodsAnnotation(WebAnnotationSet.java:287)
	at org.apache.catalina.startup.WebAnnotationSet.loadApplicationFilterAnnotations(WebAnnotationSet.java:110)
	at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:64)
	at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:415)
	at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:892)
	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:5405)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	... 6 more
Caused by: java.lang.ClassNotFoundException: SessionFactory
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1858)
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1709)
	... 20 more

tomcat启动报如上错误；于是就在找为什么报错原因；

看到这行报错：Caused by: java.lang.NoClassDefFoundError: SessionFactory应该是链接数据库方面的问题，于是检查配置文件，因为换了数据库地址，发现IP还没改，于是改成正确的Ip，和端口，再次启动，但是还是报错；

由于项目是直接copy过来的，最后索性将部署环境下/WEB-INF/classes下面的文件也一并拷贝过来，行了。

还有类似错误继续更新。每次部署项目老是会遇见这样的错误。