学到struts和hibernate整合开发一个学生管理系统时，遇到了个莫名奇妙的问题，明明我是建立了各种library而且把他导入到工程的，为什么他会提示找不到包，
这是我用到的包
比如以下异常，这明显就是没找到包的异常
java.lang.ClassNotFoundException: org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1892)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1735)
at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:495)
at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:477) at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:113)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:258) at org.apache.catalina.core.ApplicationFilterConfig.(ApplicationFilterConfig.java:105) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4958) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5652) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:899) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:875) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652) at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:679) at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1966) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
怎么回事呢？
原来是仿照老师做的时候，他用的是myeclipse，会自动把library里面的包放到lib下，但是eclipse就需要我们自己去把各种需要的包放进去了。
