单独运行任何一个项目都没有问题，但同时部署了就只能有一个项目运行，Start另一个时后台报错如下：
严重: Exception starting filter struts2 Unable to load configuration. - [unknown location] at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java: 58 ) at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java: 371 ) at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java: 424 ) at org.apache.struts2.dispatcher.FilterDispatcher.init(FilterDispatcher.java: 213 ) at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java: 275 ) at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java: 397 ) at org.apache.catalina.core.ApplicationFilterConfig. < init > (ApplicationFilterConfig.java: 108 ) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java: 3693 ) at org.apache.catalina.core.StandardContext.start(StandardContext.java: 4342 ) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java: 761 ) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java: 741 ) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java: 525 ) at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java: 920 ) at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java: 883 ) at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java: 492 ) at org.apache.catalina.startup.HostConfig.start(HostConfig.java: 1138 ) at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java: 311 ) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java: 120 ) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java: 1023 ) at org.apache.catalina.core.StandardHost.start(StandardHost.java: 719 ) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java: 1015 ) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java: 443 ) at org.apache.catalina.core.StandardService.start(StandardService.java: 448 ) at org.apache.catalina.core.StandardServer.start(StandardServer.java: 710 ) at org.apache.catalina.startup.Catalina.start(Catalina.java: 552 ) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java: 39 ) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java: 25 ) at java.lang.reflect.Method.invoke(Method.java: 597 ) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java: 288 ) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java: 413 ) Caused by: Caught exception while loading file struts - default .xml - [unknown location] at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java: 879 ) at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadDocuments(XmlConfigurationProvider.java: 161 ) at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.init(XmlConfigurationProvider.java: 130 ) at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java: 155 ) at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java: 55 ) ... 30 more Caused by: java.lang.ClassCastException: org.apache.xerces.parsers.XML11Configuration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration at org.apache.xerces.parsers.DOMParser. < init > (Unknown Source) at org.apache.xerces.parsers.DOMParser. < init > (Unknown Source) at org.apache.xerces.jaxp.DocumentBuilderImpl. < init > (Unknown Source) at org.apache.xerces.jaxp.DocumentBuilderFactoryImpl.newDocumentBuilder(Unknown Source) at com.sun.org.apache.xalan.internal.xsltc.trax.SAX2DOM. < init > (SAX2DOM.java: 69 ) at com.sun.org.apache.xalan.internal.xsltc.runtime.output.TransletOutputHandlerFactory.getSerializationHandler(TransletOutputHandlerFactory.java: 187 ) at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(TransformerImpl.java: 392 ) at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerHandlerImpl.setResult(TransformerHandlerImpl.java: 137 ) at com.opensymphony.xwork2.util.DomHelper$DOMBuilder.setup(DomHelper.java: 212 ) at com.opensymphony.xwork2.util.DomHelper$DOMBuilder. < init > (DomHelper.java: 197 ) at com.opensymphony.xwork2.util.DomHelper$DOMBuilder. < init > (DomHelper.java: 188 ) at com.opensymphony.xwork2.util.DomHelper$DOMBuilder. < init > (DomHelper.java: 174 ) at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java: 114 ) at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadConfigurationFiles(XmlConfigurationProvider.java: 870 ) ... 34 more org.apache.catalina.core.StandardContext start 严重: Error filterStart org.apache.catalina.core.StandardContext start 严重: Context [ / workmass] startup failed due to previous errors org.apache.coyote.http11.Http11AprProtocol start
搜到的解决方法：
1.发现是由于lib包冲突造成的，将两个解析xml用的jar从项目里移到tomacat的lib下面就ok了，xml-apis.jar xerces-2.6.2.jar
2.web.xml里的这个配置,我居然在两个项目里用的一样的,param-value换下就ok了,保证两个项目里不一样
<context-param>
<param-name>webAppRootKey</param-name>
<param-value>CITYSPACESystem.root</param-value>
</context-param>
据解释说 两个struts2项目 不能有相同的配置文件名。
