出现错误：Unable to load configuration.

严重: Exception starting filter struts2
Unable to load configuration. - action - file:/E:/Java/Tomcat7.0/apache-tomcat-7.0.68-windows-x64/apache-tomcat-7.0.68/webapps/SSH2Integrate/WEB-INF/classes/struts.xml:8:43
    at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:493)
    at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:74)
    at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:57)
    at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:279)
    at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:260)
    at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:105)
    at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4908)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5602)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
    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.deployDirectory(HostConfig.java:1259)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1998)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

Caused by: Unable to load configuration. - action - file:/E:/Java/Tomcat7.0/apache-tomcat-7.0.68-windows-x64/apache-tomcat-7.0.68/webapps/SSH2Integrate/WEB-INF/classes/struts.xml:8:43

    at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:70)
    at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:967)
    at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:435)
    at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:479)
    ... 19 more

Caused by: Action class [umAction] not found - action - file:/E:/Java/Tomcat7.0/apache-tomcat-7.0.68-windows-x64/apache-tomcat-7.0.68/webapps/SSH2Integrate/WEB-INF/classes/struts.xml:8:43


    at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.verifyAction(XmlConfigurationProvider.java:486)
    at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addAction(XmlConfigurationProvider.java:429)
    at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:556)
    at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:295)
    at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:112)
    at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:264)
    at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:67)
    ... 22 more

这是由于少了jar包struts2-spring-plugin-2.0.14.jar，导入jar包之后完美解决。