[b]我有一段代码，使用dom4j 正则表达式解析gml ， 代码如下： [/b]List<Element> featureMembers= root.selectNodes("featureMember"); [b]发生以下异常： [/b]java.lang.NoClassDefFoundError: org/jaxen/JaxenException     at org.dom4j.DocumentFactory.createXPath(DocumentFactory.java:230)     at org.dom4j.tree.AbstractNode.createXPath(AbstractNode.java:207)     at org.dom4j.tree.AbstractNode.selectNodes(AbstractNode.java:164)     at com.geoway.spatial.util.LocationUtils.parseTDTResponseDocument(LocationUtils.java:56)     at com.geoway.spatial.util.LocationUtils.queryTDTWFS(LocationUtils.java:33)     at com.geoway.spatial.service.impl.TDTLocationServiceImpl.getLocationByName(TDTLocationServiceImpl.java:28)     at com.geoway.spatial.service.impl.LocationAdapter.getLocationByName(LocationAdapter.java:31)     at com.geoway.spatial.service.impl.LocationAdapter.test(LocationAdapter.java:48)     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.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:297)     at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:250)     at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:144)     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:350)     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1329)     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:471)     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)     at java.security.AccessController.doPrivileged(Native Method)     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)     at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)     at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:217)     at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)     at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)     at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)     at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:429)     at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:729)     at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:381)     at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255)     at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199)     at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45)     at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3934)     at org.apache.catalina.core.StandardContext.start(StandardContext.java:4429)     at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)     at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)     at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:526)     at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:987)     at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:909)     at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:495)     at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1206)     at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:314)     at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)     at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)     at org.apache.catalina.core.StandardHost.start(StandardHost.java:722)     at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)     at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)     at org.apache.catalina.core.StandardService.start(StandardService.java:516)     at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)     at org.apache.catalina.startup.Catalina.start(Catalina.java:583)     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: java.lang.ClassNotFoundException: org.jaxen.JaxenException     at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387)     at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233)     at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)     ... 56 more 根据异常，发现少了一个类：org.jaxen.JaxenException  这个类存在jaxen.jar包中，原因可想而知了！在路径下加入这个jar包即可。