Eclipse + Tomcat 9.0 运行web项目异常：org.apache.catalina.LifecycleException: Failed to start component

异常如下：

org.apache.catalina.LifecycleException: Failed to start component [org.apache.catalina.webresources.StandardRoot@7dda48d9] 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.StandardContext.resourcesStart(StandardContext.java:4694)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:4829)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:742)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:718)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:703)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:630)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1840)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:514)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:118)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:525)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:424)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1586)
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:966)
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$StartChild.call(ContainerBase.java:1427)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1417)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:943)
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:682)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke

(NativeMethodAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke

(DelegatingMethodAccessorImpl.java:43)

at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:353)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:493)
Caused by: java.lang.IllegalArgumentException: The main resource set specified [E:\Apache\apache-tomcat-9.0.6\webapps\myweb] is not valid
at org.apache.catalina.webresources.StandardRoot.createMainResourceSet(StandardRoot.java:749)
at org.apache.catalina.webresources.StandardRoot.startInternal(StandardRoot.java:706)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
... 41 more


4月 13, 2018 8:23:36 下午 org.apache.catalina.startup.HostConfig deployDescriptor
严重: Error deploying deployment descriptor [E:\Apache\apache-tomcat-9.0.6\conf\Catalina\localhost\myweb.xml]java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [org.apache.catalina.webresources.StandardRoot@7dda48d9]
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:746)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:718)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:703)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:630)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1840)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:514)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:118)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:525)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:424)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1586)
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:966)
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$StartChild.call(ContainerBase.java:1427)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1417)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:140)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:943)
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:682)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke

(NativeMethodAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke

(DelegatingMethodAccessorImpl.java:43)

at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:353)

at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:493)

解决办法如下：

1.停止运行Tomcat：选中Tomcat 右键选择 stop；

2.删除部署的项目：选择Tomcat下部署的项目 右键 选择remove；

3.清理Tomcat：选中Tomcat 右键 Clean... ；（2、3步必须执行，否则无法修改Tomcat设置）

4.双击Tomcat，更改Tomcat设置

5. Ctrl + S 保存设置。重新部署项目，重启Tomcat。

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