tomcat启动异常：子容器启动失败（a child container failed during start）

最近在使用eclipse启动Tomcat时，发现一个问题，启动以前的项目突然报子容器启动异常。

异常信息如下：

严重: 子容器启动失败
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: 无法启动组件[org.apache.catalina.webresources.StandardRoot@15fb69cc]
	at java.util.concurrent.FutureTask.report(Unknown Source)
	at java.util.concurrent.FutureTask.get(Unknown Source)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:931)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:841)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1412)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1402)
	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)
Caused by: org.apache.catalina.LifecycleException: 无法启动组件[org.apache.catalina.webresources.StandardRoot@15fb69cc]
	at org.apache.catalina.util.LifecycleBase.handleSubClassException(LifecycleBase.java:440)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:198)
	at org.apache.catalina.core.StandardContext.resourcesStart(StandardContext.java:4803)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:4939)
	... 7 more
Caused by: java.lang.IllegalArgumentException: 指定的主资源集 [D:\eclipse4.14Code\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\Web3] 无效
	at org.apache.catalina.webresources.StandardRoot.createMainResourceSet(StandardRoot.java:747)
	at org.apache.catalina.webresources.StandardRoot.startInternal(StandardRoot.java:705)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	... 9 more

十二月 17, 2023 9:48:43 上午 org.apache.jasper.servlet.TldScanner scanJars
信息: 至少有一个JAR被扫描用于TLD但尚未包含TLD。 为此记录器启用调试日志记录，以获取已扫描但未在其中找到TLD的完整JAR列表。 在扫描期间跳过不需要的JAR可以缩短启动时间和JSP编译时间。
十二月 17, 2023 9:48:43 上午 org.apache.catalina.core.ContainerBase startInternal
严重: 子容器启动失败
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: 子容器启动失败
	at java.util.concurrent.FutureTask.report(Unknown Source)
	at java.util.concurrent.FutureTask.get(Unknown Source)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:931)
	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:766)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:688)
	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:342)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:473)
Caused by: org.apache.catalina.LifecycleException: 子容器启动失败
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:841)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1412)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1402)
	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)
Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: 无法启动组件[org.apache.catalina.webresources.StandardRoot@15fb69cc]
	at java.util.concurrent.FutureTask.report(Unknown Source)
	at java.util.concurrent.FutureTask.get(Unknown Source)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:931)
	... 8 more
Caused by: org.apache.catalina.LifecycleException: 无法启动组件[org.apache.catalina.webresources.StandardRoot@15fb69cc]
	at org.apache.catalina.util.LifecycleBase.handleSubClassException(LifecycleBase.java:440)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:198)
	at org.apache.catalina.core.StandardContext.resourcesStart(StandardContext.java:4803)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:4939)
	... 7 more
Caused by: java.lang.IllegalArgumentException: 指定的主资源集 [D:\eclipse4.14Code\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\Web3] 无效
	at org.apache.catalina.webresources.StandardRoot.createMainResourceSet(StandardRoot.java:747)
	at org.apache.catalina.webresources.StandardRoot.startInternal(StandardRoot.java:705)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	... 9 more

十二月 17, 2023 9:48:43 上午 org.apache.catalina.startup.Catalina start
严重: 所必需的服务组件启动失败，所以无法启动Tomcat
org.apache.catalina.LifecycleException: 子容器启动失败
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942)
	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:766)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:688)
	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:342)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:473)
Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: 子容器启动失败
	at java.util.concurrent.FutureTask.report(Unknown Source)
	at java.util.concurrent.FutureTask.get(Unknown Source)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:931)
	... 13 more
Caused by: org.apache.catalina.LifecycleException: 子容器启动失败
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:841)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1412)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1402)
	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)
Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: 无法启动组件[org.apache.catalina.webresources.StandardRoot@15fb69cc]
	at java.util.concurrent.FutureTask.report(Unknown Source)
	at java.util.concurrent.FutureTask.get(Unknown Source)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:931)
	... 8 more
Caused by: org.apache.catalina.LifecycleException: 无法启动组件[org.apache.catalina.webresources.StandardRoot@15fb69cc]
	at org.apache.catalina.util.LifecycleBase.handleSubClassException(LifecycleBase.java:440)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:198)
	at org.apache.catalina.core.StandardContext.resourcesStart(StandardContext.java:4803)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:4939)
	... 7 more
Caused by: java.lang.IllegalArgumentException: 指定的主资源集 [D:\eclipse4.14Code\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\Web3] 无效
	at org.apache.catalina.webresources.StandardRoot.createMainResourceSet(StandardRoot.java:747)
	at org.apache.catalina.webresources.StandardRoot.startInternal(StandardRoot.java:705)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	... 9 more

我们从上面那么长的错误信息中提取关键字眼如下

Caused by: java.lang.IllegalArgumentException: 指定的主资源集 [D:\eclipse4.14Code\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\Web3] 无效

我们可以清晰的读到加载Web3这个项目无效

于是我们找到Server这个工程

这个Server工程是我们在启动Tomcat时自动生成的一个工程，该工程里面包含Tomcat的重要信息，切记不可以删除掉。这里可以看到我运行了4个Tomcat，所以会出现四个Tomcat的文件夹，每一个Tomcat文件夹包含当前Tomcat配置的重要信息，我们打开红色箭头指向的文件

红色框框处的这行代码是以前Tomcat运行Web3这个项目时生成的一条记录，
现在Web3这个项目既然已经无法运行了，我们将其注释掉重启即可解决问题

最终运营结果：

看到箭头处表明我们的Tomcat工程启动成功