实践证明，Struts2.3.16.3 至少要下面9个Jar包才能正常启动。
commons-fileupload-1.3.1.jar
commons-logging-1.1.3.jar
freemarker-2.3.19.jar
javassist-3.11.0.GA.jar
ognl-3.0.6.jar
struts2-core-2.3.16.3.jar
xwork-core-2.3.16.3.jar
commons-io-2.2.jar
commons-lang3-3.1.jar
少javassist-3.11.0.GA.jar报这个错：
严重: Dispatcher initialization failed java.lang.RuntimeException: java.lang.reflect.InvocationTargetException at com.opensymphony.xwork2.inject.ContainerImpl$MethodInjector.inject(ContainerImpl.java:301) at com.opensymphony.xwork2.inject.ContainerImpl$ConstructorInjector.construct(ContainerImpl.java:438) at com.opensymphony.xwork2.inject.ContainerBuilder$5.create(ContainerBuilder.java:207) at com.opensymphony.xwork2.inject.Scope$2$1.create(Scope.java:51) at com.opensymphony.xwork2.inject.ContainerBuilder$3.create(ContainerBuilder.java:93) at com.opensymphony.xwork2.inject.ContainerBuilder$7.call(ContainerBuilder.java:487) at com.opensymphony.xwork2.inject.ContainerBuilder$7.call(ContainerBuilder.java:484) at com.opensymphony.xwork2.inject.ContainerImpl.callInContext(ContainerImpl.java:584) at com.opensymphony.xwork2.inject.ContainerBuilder.create(ContainerBuilder.java:484) at com.opensymphony.xwork2.config.impl.DefaultConfiguration.createBootstrapContainer(DefaultConfiguration.java:340) at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:229) at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:67) at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:445) at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:489) 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:273) at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:254) at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:372) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:98) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4542) at org.apache.catalina.core.StandardContext$2.call(StandardContext.java:5220) at org.apache.catalina.core.StandardContext$2.call(StandardContext.java:5215) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.opensymphony.xwork2.inject.ContainerImpl$MethodInjector.inject(ContainerImpl.java:299) ... 26 more Caused by: java.lang.ExceptionInInitializerError at com.opensymphony.xwork2.ognl.OgnlValueStackFactory.setContainer(OgnlValueStackFactory.java:84) ... 31 more Caused by: java.lang.IllegalArgumentException: Javassist library is missing in classpath! Please add missed dependency! at ognl.OgnlRuntime.<clinit>(OgnlRuntime.java:168) ... 32 more Caused by: java.lang.ClassNotFoundException: javassist.ClassPool at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1676) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at ognl.OgnlRuntime.<clinit>(OgnlRuntime.java:165) ... 32 more
少commons-io-2.2.jar报这个错：
java.lang.NoClassDefFoundError: org/apache/commons/io/FileUtils at com.opensymphony.xwork2.util.fs.JarEntryRevision.build(JarEntryRevision.java:50) at com.opensymphony.xwork2.util.fs.DefaultFileManager.monitorFile(DefaultFileManager.java:97) at com.opensymphony.xwork2.util.fs.DefaultFileManager.loadFile(DefaultFileManager.java:74) at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java:1011) at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadDocuments(XmlConfigurationProvider.java:165) at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.init(XmlConfigurationProvider.java:132) at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:233) at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:67) at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:445) at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:489) 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:273) at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:254) at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:372) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:98) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4542) at org.apache.catalina.core.StandardContext$2.call(StandardContext.java:5220) at org.apache.catalina.core.StandardContext$2.call(StandardContext.java:5215) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.ClassNotFoundException: org.apache.commons.io.FileUtils at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1676) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521) ... 23 more
少commons-lang3-3.1.jar报这个错：
java.lang.NoClassDefFoundError: org/apache/commons/lang3/StringUtils at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:211) at org.apache.struts2.config.StrutsXmlConfigurationProvider.register(StrutsXmlConfigurationProvider.java:102) at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:234) at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:67) at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:445) at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:489) 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:273) at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:254) at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:372) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:98) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4542) at org.apache.catalina.core.StandardContext$2.call(StandardContext.java:5220) at org.apache.catalina.core.StandardContext$2.call(StandardContext.java:5215) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.ClassNotFoundException: org.apache.commons.lang3.StringUtils at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1676) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521) ... 19 more