tomcat启动报错：org.apache.catalina.deploy.WebXml addFilter

SEVERE: End event threw exception
java.lang.NoSuchMethodException: org.apache.catalina.deploy.WebXml addFilter
    at org.apache.tomcat.util.IntrospectionUtils.callMethod1(IntrospectionUtils.java:855)
    at org.apache.tomcat.util.digester.SetNextRule.end(SetNextRule.java:201)
    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1063)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:606)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1742)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2900)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:489)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
    at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1561)
    at org.apache.catalina.startup.ContextConfig.parseWebXml(ContextConfig.java:1809)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1247)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:873)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:371)
    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:5355)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1229)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
六月 12, 2014 7:22:06 下午 org.apache.catalina.startup.ContextConfig parseWebXml
SEVERE: Parse error in application web.xml file at jndi:/localhost/carManager/WEB-INF/web.xml
org.xml.sax.SAXParseException; systemId: jndi:/localhost/carManager/WEB-INF/web.xml; lineNumber: 33; columnNumber: 11; Error at (33, 11) : org.apache.catalina.deploy.WebXml addFilter
    at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2711)
    at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2743)
    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1066)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:606)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1742)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2900)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:489)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
    at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1561)
    at org.apache.catalina.startup.ContextConfig.parseWebXml(ContextConfig.java:1809)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1247)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:873)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:371)
    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:5355)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1229)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.NoSuchMethodException: org.apache.catalina.deploy.WebXml addFilter
    at org.apache.tomcat.util.IntrospectionUtils.callMethod1(IntrospectionUtils.java:855)
    at org.apache.tomcat.util.digester.SetNextRule.end(SetNextRule.java:201)
    at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1063)
    ... 30 more
六月 12, 2014 7:22:06 下午 org.apache.catalina.startup.ContextConfig parseWebXml
SEVERE: Occurred at line 33 column 11
六月 12, 2014 7:22:06 下午 org.apache.catalina.startup.ContextConfig configureStart
SEVERE: Marking this application unavailable due to previous error(s)
六月 12, 2014 7:22:06 下午 org.apache.catalina.core.StandardContext startInternal
SEVERE: Error getConfigured
六月 12, 2014 7:22:06 下午 org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/carManager] startup failed due to previous errors

   解决办法：

    在tomacat的配置文件context.xml里加上<Loader delegate="true"/>

   <Loader delegate="true"/>此参数的作用：

首先，你需要了解一下JVM的Classloader机制(详细请自行google之)。
简而言之，JVM的classloader加载继承关系分为BootstarpClassLoader --> ExtClassLoader --> SystemClassLoader，应用的WebAppClassLoader继承自SystemClassLoader，在加载具体某个类时，一般会先委托给父类ClassLoader，当父类ClassLoader无法加载成功时，才会再由子类ClassLoader尝试加载，这就是所谓的delegate机制。

其次，Tomcat在jvm的ClassLoader机制上增加了几个继承层次。
SystemClassLoader --> CommonClassLoader -->(ServerClassLoader | SharedClassLoader --> WebAppClassLoader)。
CommonClassLoader用来加载${CATALINA_HOME}/conf/catalina.properties中common.loader配置目录下的类文件，一般是用来加载${CATALINA_HOME}/lib下的文件。该loader加载的类为tomcat服务器和tomcat下面的所有webApp所共享。
ServerClassLoader用来加载${CATALINA_HOME}/conf/catalina.properties中server.loader配置目录下的类文件，一般是用来加载${CATALINA_HOME}/server下的文件。该loader加载的类为tomcat服务器所独有核心类，tomcat下面的WebApp无法访问。
SharedClassLoader用来加载${CATALINA_HOME}/conf/catalina.properties中shared.loader配置目录下的类文件，一般是用来加载${CATALINA_HOME}/shared下的文件。该loader加载的类为tomcat下面的所有webApp所共享。
WebAppClassLoader用来加载${CATALINA_HOME}/webapps/目录下每个WebApp应用的/WEB-INF/class，/WEB-INF/lib的类文件，每个WebApp对应一个WebAppClassLoader，用来加载其所需要的类文件。

最后，说一下delegate配置的意义。
True，表示tomcat将遵循JVM的delegate机制，即一个WebAppClassLoader在加载类文件时，会先递交给SharedClassLoader加载，SharedClassLoader无法加载成功，会继续向自己的父类委托，一直到BootstarpClassLoader，如果都没有加载成功，则最后由WebAppClassLoader自己进行加载。
False，表示将不遵循这个delegate机制，即WebAppClassLoader在加载类文件时，会优先自己尝试加载，如果加载失败，才会沿着继承链，依次委托父类加载。

在此说一下配置为False需要注意的问题：一旦配置为False，如果你在WebApp中自己定义了一个java.lang.String，则这个String类会有可能覆盖掉jdk中的String类，这也许不是你想要的结果。另外对于多个WebApp公用jar包，你可能会放到${CATALINA_HOME}/shared目录中共享，但是一不小心在应用的/WEB-INF/lib中也包含了一个同名的但版本不一致的jar的话，这就有可能会导致很多奇怪的问题。