以下方法亲测有效，感谢万能的网友。
严重: End event threw exception
java.lang.NoSuchMethodException: org.apache.catalina.deploy.WebXml addServlet
at org.apache.tomcat.util.IntrospectionUtils.callMethod1(IntrospectionUtils.java:849)
at org.apache.tomcat.util.digester.SetNextRule.end(SetNextRule.java:201)
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:1856)
at org.apache.catalina.startup.ContextConfig.getDefaultWebXmlFragment(ContextConfig.java:1494)
at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1255)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:887)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:387)
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.deployDescriptor(HostConfig.java:679)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1966)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
这里需要将tomcat文件路径下conf→context.xml进行修改，添加<Loader delegate="true"/>即可解决这个问题：
<Context>
<!-- Default set of monitored resources -->
<WatchedResource>WEB-INF/web.xml</WatchedResource>
<Loader delegate="true"/>
<!-- Uncomment this to disable session persistence across Tomcat restarts -->
<!--
<Manager pathname="" />
-->
<!-- Uncomment this to enable Comet connection tacking (provides events
on session expiration as well as webapp lifecycle) -->
<!--
<Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
-->
</Context>