java - struts2找不到类文件

Question

刚学到struts2这块，按照书上的代码观察struts2的action的运行情况,然后也是按照书上的步骤，先是导入包，然后配置web.xml和在src文件夹中配置一个struts.xml,最后编写一个index.jsp和first.jsp，然而在运行时候出了错误,报错情况为:
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:1892)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1735)
at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:504)
at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:486)
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.<init>(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$StartChild.call(ContainerBase.java:1571)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1561)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

尝试解决过程:
网上查找过问题，有的答案说是有可能是包重复了？然后我根据这种做法重新导入了jar包，可是依然报错，然后还有的解决方案是说看下struts.xml和web.xml，看看是否有拼写错误或其它小问题，可是我观察了好久，没有看到出错的地方。
以下是我的页面出错情况、项目文件，以及配置情况:

希望路过的大佬能指教下，小弟感激不尽...

Answer 1

The problem has been solved.
1. The specified page cannot be found
java.lang.ClassNotFoundException: org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
The solution is: <filter-class>org.apache.struts2.dispatcher.ng.filter The class path in .StrutsPrepareAndExecuteFilter</filter-class>
is changed to: org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter

2. Other problems occurred after the change: tomcat could not start normally and reported many errors.
Solution: Add another jar package: log4j-api-2.7.jar

At this point, tomcat starts normally, struts2 can also accurately intercept objects, and the page displays normally.

Answer 2

Check if the project’s build path contains the packages you added.

Answer 3

You did not import the package into the classpath