weblogic下的jar包冲突问题
最近工作上遇到一个奇怪的技术问题，记录下。
我们服务器是多节点部署的，一共是4台服务器，是通过apache转发到每台服务器的（负载均衡），每台服务器的架构都是一样的，都是用weblogic作为服务器端的，项目应用是用SSH架构。
问题就出在5,7.8节点的服务器都没有问题，就6节点的服务器出了问题（假设4台服务器部署在内网的5,6,7,8节点上）
每次访问到6节点就挂了，后来查看错误日志，错误日志如下：
2013-09-05 18:47:57,848 ERROR [[ACTIVE] ExecuteThread: '10' for queue: 'weblogic.kernel.Default (self-tuning)'] action.ActionServlet (ActionServlet.java:1034) - Parsing error pr
ocessing resource path
/WEB-INF/struts-cfg/struts-config-user.xml,
/WEB-INF/struts-cfg/struts-config-centrex.xml
java.net.UnknownHostException: struts.apache.org
at java.net.InetAddress.getAllByName0(InetAddress.java:1184)
at java.net.InetAddress.getAllByName(InetAddress.java:1110)
at java.net.InetAddress.getAllByName(InetAddress.java:1046)
at weblogic.net.http.HttpClient.openServer(HttpClient.java:309)
at weblogic.net.http.HttpClient.openServer(HttpClient.java:425)
at weblogic.net.http.HttpClient.New(HttpClient.java:252)
at weblogic.net.http.HttpURLConnection.getHttpClient(HttpURLConnection.java:228)
at weblogic.net.http.HttpURLConnection.getInputStream(HttpURLConnection.java:450)
at weblogic.net.http.SOAPHttpURLConnection.getInputStream(SOAPHttpURLConnection.java:37)
at org.apache.commons.digester.Digester.createInputSourceFromURL(Digester.java:1938)
at org.apache.commons.digester.Digester.resolveEntity(Digester.java:1615)
at weblogic.xml.jaxp.ChainingEntityResolver.resolveEntity(ChainingEntityResolver.java:87)
at weblogic.xml.jaxp.ChainingEntityResolver.resolveEntity(ChainingEntityResolver.java:87)
at com.sun.org.apache.xerces.internal.util.EntityResolverWrapper.resolveEntity(EntityResolverWrapper.java:107)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.resolveEntityAsPerStax(XMLEntityManager.java:1017)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.dispatch(XMLDocumentScannerImpl.java:1189)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.next(XMLDocumentScannerImpl.java:1087)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:1000)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:647)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
at weblogic.xml.jaxp.WebLogicXMLReader.parse(WebLogicXMLReader.java:133)
at weblogic.xml.jaxp.RegistryXMLReader.parse(RegistryXMLReader.java:173)
at org.apache.commons.digester.Digester.parse(Digester.java:1745)
at org.apache.struts.action.ActionServlet.parseModuleConfigFile(ActionServlet.java:1006)
at org.apache.struts.action.ActionServlet.initModuleConfig(ActionServlet.java:955)
at org.apache.struts.action.ActionServlet.init(ActionServlet.java:470)
at javax.servlet.GenericServlet.init(GenericServlet.java:241)
at weblogic.servlet.internal.StubSecurityHelper$ServletInitAction.run(StubSecurityHelper.java:283)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
at weblogic.servlet.internal.StubSecurityHelper.createServlet(StubSecurityHelper.java:64)
at weblogic.servlet.internal.StubLifecycleHelper.createOneInstance(StubLifecycleHelper.java:58)
at weblogic.servlet.internal.StubLifecycleHelper.<init>(StubLifecycleHelper.java:48)
at weblogic.servlet.internal.ServletStubImpl.prepareServlet(ServletStubImpl.java:539)
at weblogic.servlet.internal.WebAppServletContext.preloadServlet(WebAppServletContext.java:1981)
at weblogic.servlet.internal.WebAppServletContext.loadServletsOnStartup(WebAppServletContext.java:1955)
at weblogic.servlet.internal.WebAppServletContext.preloadResources(WebAppServletContext.java:1874)
at weblogic.servlet.internal.WebAppServletContext.start(WebAppServletContext.java:3154)
at weblogic.servlet.internal.WebAppModule.startContexts(WebAppModule.java:1518)
at weblogic.servlet.internal.WebAppModule.start(WebAppModule.java:484)
at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:425)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:52)
at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:119)
at weblogic.application.internal.flow.ScopedModuleDriver.start(ScopedModuleDriver.java:200)
at weblogic.application.internal.flow.ModuleListenerInvoker.start(ModuleListenerInvoker.java:247)
at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:425)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:52)
at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:119)
at weblogic.application.internal.flow.StartModulesFlow.activate(StartModulesFlow.java:27)
at weblogic.application.internal.BaseDeployment$2.next(BaseDeployment.java:671)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:52)
at weblogic.application.internal.BaseDeployment.activate(BaseDeployment.java:212)
at weblogic.application.internal.SingleModuleDeployment.activate(SingleModuleDeployment.java:44)
at weblogic.application.internal.DeploymentStateChecker.activate(DeploymentStateChecker.java:161)
at weblogic.deploy.internal.targetserver.AppContainerInvoker.activate(AppContainerInvoker.java:79)
at weblogic.deploy.internal.targetserver.operations.AbstractOperation.activate(AbstractOperation.java:569)
at weblogic.deploy.internal.targetserver.operations.ActivateOperation.activateDeployment(ActivateOperation.java:150)
at weblogic.deploy.internal.targetserver.operations.ActivateOperation.doCommit(ActivateOperation.java:116)
at weblogic.deploy.internal.targetserver.operations.AbstractOperation.commit(AbstractOperation.java:323)
at weblogic.deploy.internal.targetserver.DeploymentManager.handleDeploymentCommit(DeploymentManager.java:844)
at weblogic.deploy.internal.targetserver.DeploymentManager.activateDeploymentList(DeploymentManager.java:1253)
at weblogic.deploy.internal.targetserver.DeploymentManager.handleCommit(DeploymentManager.java:440)
at weblogic.deploy.internal.targetserver.DeploymentServiceDispatcher.commit(DeploymentServiceDispatcher.java:163)
at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.doCommitCallback(DeploymentReceiverCallbackDeliverer.java:195)
at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.access$100(DeploymentReceiverCallbackDeliverer.java:13)
at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer$2.run(DeploymentReceiverCallbackDeliverer.java:68)
at weblogic.work.SelfTuningWorkManagerImpl$WorkAdapterImpl.run(SelfTuningWorkManagerImpl.java:545)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)
开始一直以为是6节点上的服务器解析struts-config.xml配置文件的路径出错了（因为它的报错提示也确实是提示这个错，误导啊），换了struts-config.xml配置文件的路径，还是这个错，基本上可以排除不是路径问题了。
网上查了下资料，有些说是:
struts-config.xml 的头声明不对，说是要把
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN" "http://struts.apache.org/dtds/struts-config_1_2.dtd">
换成
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.1//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd">
就可以了。
试了一下，还是不行。
折腾了一天，该排除的都排除了，根据经验，只能把问题定位在jar包冲突上了，后来看了看lib下的struts包：
-rw-r--r-- 1 weblogic app 438203 8月 19 18:28 struts.jar
-rw-r--r-- 1 weblogic app 328896 8月 19 18:28 struts-core-1.3.8.jar
-rw-r--r-- 1 weblogic app 39644 8月 19 18:28 struts-extras-1.3.8.jar
-rw-r--r-- 1 weblogic app 251521 8月 19 18:28 struts-taglib-1.3.8.jar
-rw-r--r-- 1 weblogic app 119653 8月 19 18:28 struts-tiles-1.3.8.jar
我记得struts.jar 和 struts-core-1.3.8.jar 包起的作用是一样了，会不会因为服务器加载jar包的顺序不一样，导致只加载了一个，而这个却不能找到struts-config.xml的路径？ 于是把struts.jar重命名了，如下：
-rw-r--r-- 1 weblogic app 438203 8月 19 18:28 struts.jar.zk
-rw-r--r-- 1 weblogic app 328896 8月 19 18:28 struts-core-1.3.8.jar
-rw-r--r-- 1 weblogic app 39644 8月 19 18:28 struts-extras-1.3.8.jar
-rw-r--r-- 1 weblogic app 251521 8月 19 18:28 struts-taglib-1.3.8.jar
-rw-r--r-- 1 weblogic app 119653 8月 19 18:28 struts-tiles-1.3.8.jar
然后重启了weblogic服务器，不报错了，浏览器访问也ok了。果然是jar包冲突问题。是因为weblogic加载jar包的顺序不一样导致的。
但是一直想不明白的是5,7,8节点为什么就可以？ 四台服务器的配置都是一模一样的。待求解。