tomcat部署war文件之后无法启动项目

错误如下：

严重: End event threw exception

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 org.apache.tomcat.util.IntrospectionUtils.callMethodN(IntrospectionUtils.java:905)

    at org.apache.catalina.startup.CallMethodMultiRule.end(WebRuleSet.java:1021)

    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1060)

    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(Unknown Source)

    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(Unknown Source)

    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)

    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)

    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)

    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)

    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)

    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)

    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)

    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)

    at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1555)

    at org.apache.catalina.startup.ContextConfig.parseWebXml(ContextConfig.java:1858)

    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1263)

    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:889)

    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:386)

    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)

    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)

    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5472)

    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)

    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:899)

    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:875)

    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)

    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1091)

    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1980)

    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)

    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)

    at java.util.concurrent.FutureTask.run(Unknown Source)

    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)

    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

    at java.lang.Thread.run(Unknown Source)

Caused by: java.lang.IllegalArgumentException: The servlets named [xmlServlet] and [xmlServlet] are both mapped to the url-pattern [/servlet/xmlServlet] which is not permitted

    at org.apache.catalina.deploy.WebXml.addServletMapping(WebXml.java:293)

    ... 37 more

2016-3-19 14:44:38 org.apache.catalina.startup.ContextConfig parseWebXml

严重: Parse error in application web.xml file at jndi:/localhost/znld/WEB-INF/web.xml

java.lang.IllegalArgumentException: The servlets named [xmlServlet] and [xmlServlet] are both mapped to the url-pattern [/servlet/xmlServlet] which is not permitted

    at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2705)

    at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2737)

    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1063)

    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(Unknown Source)

    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(Unknown Source)

    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)

    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)

    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)

    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)

    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)

    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)

    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)

    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)

    at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1555)

    at org.apache.catalina.startup.ContextConfig.parseWebXml(ContextConfig.java:1858)

    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1263)

    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:889)

    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:386)

    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)

    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)

    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5472)

    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)

    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:899)

    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:875)

    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)

    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1091)

    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1980)

    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)

    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)

    at java.util.concurrent.FutureTask.run(Unknown Source)

    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)

    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

    at java.lang.Thread.run(Unknown Source)

Caused by: java.lang.IllegalArgumentException: The servlets named [xmlServlet] and [xmlServlet] are both mapped to the url-pattern [/servlet/xmlServlet] which is not permitted

    at org.apache.catalina.deploy.WebXml.addServletMapping(WebXml.java:293)

    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 org.apache.tomcat.util.IntrospectionUtils.callMethodN(IntrospectionUtils.java:905)

    at org.apache.catalina.startup.CallMethodMultiRule.end(WebRuleSet.java:1021)

    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1060)

    ... 30 more

==========================分割线=====================================

错误为红色字体所示：The servlets named [xmlServlet] and [xmlServlet] are both mapped to the url-pattern [/servlet/xmlServlet] which is not permitted

web.xml文件中重复定义了一个变量：

<servlet-mapping>

        <servlet-name>xmlServlet</servlet-name>

        <url-pattern>/servlet/xmlServlet</url-pattern>

   </servlet-mapping>

<servlet-mapping>

        <servlet-name>xmlServlet</servlet-name>

        <url-pattern>/servlet/xmlServlet</url-pattern>

    </servlet-mapping>

删除重复参数之后启动正常。