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.pluginsorg.eclipse.wst.server.core mp0wtpwebappsWeb3] 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.pluginsorg.eclipse.wst.server.core mp0wtpwebappsWeb3] 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.pluginsorg.eclipse.wst.server.core mp0wtpwebappsWeb3] 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.pluginsorg.eclipse.wst.server.core mp0wtpwebappsWeb3] 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