项目启动异常:Exception: java.lang.RuntimeException: XPathFactory#newInstance()

　　项目启动时，报如下异常： **** MessageBrokerServlet failed to initialize due to runtime exception: Exception: java.lang.RuntimeException: XPathFactory#newInstance() failed to create an XPathFactory for the default object model: http://java.sun.com/jaxp/xpath/dom with the XPathFactoryConfigurationException: javax.xml.xpath.XPathFactoryConfigurationException : No XPathFctory implementation found for the object model: http://java.sun.com/jaxp/xpath/dom at javax.xml.xpath.XPathFactory.newInstance(Unknown Source) at flex.messaging.config.XPathServerConfigurationPars er.initializeExpressionQuery(XPathServerConfigurati onParser.java:46) at flex.messaging.config.AbstractConfigurationParser. parse(AbstractConfigurationParser.java:68) at flex.messaging.config.FlexConfigurationManager.get MessagingConfiguration(FlexConfigurationManager.jav a:79) at flex.messaging.MessageBrokerServlet.init(MessageBr okerServlet.java:106) at org.apache.catalina.core.StandardWrapper.loadServl et(StandardWrapper.java:1139) at org.apache.catalina.core.StandardWrapper.load(Stan dardWrapper.java:966) at org.apache.catalina.core.StandardContext.loadOnSta rtup(StandardContext.java:3956) at org.apache.catalina.core.StandardContext.start(Sta ndardContext.java:4230) at org.apache.catalina.core.ContainerBase.addChildInt ernal(ContainerBase.java:760) at org.apache.catalina.core.ContainerBase.addChild(Co ntainerBase.java:740) at org.apache.catalina.core.StandardHost.addChild(Sta ndardHost.java:544) at org.apache.catalina.startup.HostConfig.deployDirec tory(HostConfig.java:926) at org.apache.catalina.startup.HostConfig.deployDirec tories(HostConfig.java:889) at org.apache.catalina.startup.HostConfig.deployApps( HostConfig.java:492) at org.apache.catalina.startup.HostConfig.start(HostC onfig.java:1149) at org.apache.catalina.startup.HostConfig.lifecycleEv ent(HostConfig.java:311) at org.apache.catalina.util.LifecycleSupport.fireLife cycleEvent(LifecycleSupport.java:120) at org.apache.catalina.core.ContainerBase.start(Conta inerBase.java:1022) at org.apache.catalina.core.StandardHost.start(Standa rdHost.java:736) at org.apache.catalina.core.ContainerBase.start(Conta inerBase.java:1014) at org.apache.catalina.core.StandardEngine.start(Stan dardEngine.java:443) at org.apache.catalina.core.StandardService.start(Sta ndardService.java:448) at org.apache.catalina.core.StandardServer.start(Stan dardServer.java:700) at org.apache.catalina.startup.Catalina.start(Catalin a.java:552) at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.catalina.startup.Bootstrap.start(Bootst rap.java:295) at org.apache.catalina.startup.Bootstrap.main(Bootstr ap.java:433) 11/03/29 09:36:57 ERROR [main] [/hgwl].loadOnStartup(3958) | Servlet /hgwl threw load() exception javax.servlet.UnavailableException: XPathFactory#newInstance() failed to create an XPathFactory for the default object model: http://java.sun.com/jaxp/xpath/dom with the XPathFactoryConfigurationException: javax.xml.xpath.XPathFactoryConfigurationException : No XPathFctory implementation found for the object model: http://java.sun.com/jaxp/xpath/dom at flex.messaging.MessageBrokerServlet.init(MessageBr okerServlet.java:170) at org.apache.catalina.core.StandardWrapper.loadServl et(StandardWrapper.java:1139) at org.apache.catalina.core.StandardWrapper.load(Stan dardWrapper.java:966) at org.apache.catalina.core.StandardContext.loadOnSta rtup(StandardContext.java:3956) at org.apache.catalina.core.StandardContext.start(Sta ndardContext.java:4230) at org.apache.catalina.core.ContainerBase.addChildInt ernal(ContainerBase.java:760) at org.apache.catalina.core.ContainerBase.addChild(Co ntainerBase.java:740) at org.apache.catalina.core.StandardHost.addChild(Sta ndardHost.java:544) at org.apache.catalina.startup.HostConfig.deployDirec tory(HostConfig.java:926) at org.apache.catalina.startup.HostConfig.deployDirec tories(HostConfig.java:889) at org.apache.catalina.startup.HostConfig.deployApps( HostConfig.java:492) at org.apache.catalina.startup.HostConfig.start(HostC onfig.java:1149) at org.apache.catalina.startup.HostConfig.lifecycleEv ent(HostConfig.java:311) at org.apache.catalina.util.LifecycleSupport.fireLife cycleEvent(LifecycleSupport.java:120) at org.apache.catalina.core.ContainerBase.start(Conta inerBase.java:1022) at org.apache.catalina.core.StandardHost.start(Standa rdHost.java:736) at org.apache.catalina.core.ContainerBase.start(Conta inerBase.java:1014) at org.apache.catalina.core.StandardEngine.start(Stan dardEngine.java:443) at org.apache.catalina.core.StandardService.start(Sta ndardService.java:448) at org.apache.catalina.core.StandardServer.start(Stan dardServer.java:700) at org.apache.catalina.startup.Catalina.start(Catalin a.java:552) at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.catalina.startup.Bootstrap.start(Bootst rap.java:295) at org.apache.catalina.startup.Bootstrap.main(Bootstr ap.java:433) 解决方法：在工程中加入 xalan.jar (我只加了这个就可以)，xerces-2.6.2.jar，xercesImpl.jar，xml-apis.jar。