求助！还是Server Tomcat v9.0 Server at localhost failed to start.

[rebornyp]

用了Eclipse一年多了，最近两个月没起sever，昨天试了下启一个新版本的tomcat 9.0，没想到突然就fail to start了，
报错内容就一句话-Server Tomcat v9.0 Server at localhost failed to start.（多么熟悉的报错内容啊！）
出了问题就找原因，我首先查看了下我旧版本的tomcat 7.0能否正常启动，没问题，可以。然后去网上查了下，说双击sever设置其配置文件里
上图中的Server Location我试了选择下面的 Use Tomcat Installation，好办法，我发现tomcat可以启动了，但是查看了下Console后台，竟然有报错！我对比了下启动tomcat 7时是没有报错的，而启动tomcat 8.0后会报错，但还是启动了，因为tomcat首页可以正常访问了。下面是tomcat 8.0的可以启动但是报错代码及截图如下：

org.apache.catalina.LifecycleException: Failed to start component [FormAuthenticator[StandardEngine[Catalina].StandardHost[localhost].StandardContext[/examples]]]
	at org.apache.catalina.util.LifecycleBase.handleSubClassException(LifecycleBase.java:441)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:198)
	at org.apache.catalina.core.StandardPipeline.startInternal(StandardPipeline.java:179)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5015)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:740)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:716)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:703)
	at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1134)
	at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1868)
	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
	at java.util.concurrent.AbstractExecutorService.submit(Unknown Source)
	at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1045)
	at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:433)
	at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1578)
	at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:308)
	at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
	at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:424)
	at org.apache.catalina.util.LifecycleBase.setState(LifecycleBase.java:367)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:964)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:839)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1425)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1415)
	at java.util.concurrent.FutureTask.run(Unknown Source)
	at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
	at java.util.concurrent.AbstractExecutorService.submit(Unknown Source)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:941)
	at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:258)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:770)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:671)
	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.catalina.startup.Bootstrap.start(Bootstrap.java:355)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:495)
Caused by: java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lang/String;
	at org.apache.catalina.authenticator.AuthenticatorBase.startInternal(AuthenticatorBase.java:1138)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	... 42 more
~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~
~~~~~~~~~~~~
信息: Server startup in 530 ms