由於疏忽，給web.xml配置servelet的時候出現了問題。配置<url-pattern>/hello</url-pattern>的時候少了斜線，tomcat啟動不了。

    <servlet>
        <servlet-name>MyServlet</servlet-name>
        <servlet-class>com.itheima.MyServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name
 
>MyServlet</servlet-name>
        <!-- 少了/會導致tomcat啟動失敗 -->
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>

錯誤日誌如下：
嚴重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/WebApp01]]
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:1120)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:819)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
at org.apache.catalina.core.ContainerBaseS

tartChild.call(ContainerBase.java:1572)atorg.apache.catalina.core.ContainerBaseStartChild.call(ContainerBase.java:1562)
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: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/WebApp01]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
… 6 more
Caused by: java.lang.IllegalArgumentException: Invalid hello in servlet mapping
at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3379)
at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3354)
at org.apache.catalina.deploy.WebXml.configureContext(WebXml.java:1438)
at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1357)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:889)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:386)
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:5472)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
… 6 more

十一月 20, 2017 11:07:33 上午 org.apache.catalina.core.ContainerBase startInternal
嚴重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
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:1120)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:444)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:738)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
at org.apache.catalina.startup.Catalina.start(Catalina.java:693)
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:294)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
at org.apache.catalina.core.ContainerBaseStartChild.call(ContainerBase.java:1572)atorg.apache.catalina.core.ContainerBaseStartChild.call(ContainerBase.java:1562)
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: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1128)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:819)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
… 6 more

十一月 20, 2017 11:07:33 上午 org.apache.catalina.startup.Catalina start
嚴重: The required Server component failed to start so Tomcat is unable to start.
org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
at org.apache.catalina.startup.Catalina.start(Catalina.java:693)
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:294)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:738)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
… 7 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:444)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
… 9 more
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1128)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
… 11 more