本篇文章主要说的是我在用MyEclipse安装Struts2时报错的情况，以及解决方法。
版本：MyEclipse为2016版，Struts2为Struts2-2.5.5版。
报错内容：
严重: Exception starting filter struts2 java.lang.ClassNotFoundException: org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1284) at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1118) at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:520) at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:501) at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:118) at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:258) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:105) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4561) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5204) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:152) at org.apache.catalina.startup.HostConfig.reload(HostConfig.java:1386) at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1350) at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1586) at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:280) at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94) at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1136) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1372) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1376) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1344) at java.lang.Thread.run(Thread.java:745) 三月 13, 2017 9:04:00 上午 org.apache.catalina.core.StandardContext startInternal 严重: One or more Filters failed to start. Full details will be found in the appropriate container log file 三月 13, 2017 9:04:00 上午 org.apache.catalina.core.StandardContext startInternal 严重: Context [/Struts_HelloWorld] startup failed due to previous errors 以上就是报错内容。我的修改方式：
在project下的WebRoot下面的WEB-INF下面有个lib文件夹。lib目录就是用来导入Struts2 的jar包。报错原因我觉得可能是因为里面的一个jar版本不对，于是我将原来的struts2-core-2.5.5.jar换成struts2-core-2.3.24.1.jar。然后就能正常运行了。
