严重: 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:916)  
    at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)  
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)  
    at org.apache.catalina.core.StandardService.startInternal(StandardService.java:439)  
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)  
    at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:769)  
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)  
    at org.apache.catalina.startup.Catalina.start(Catalina.java:625)  
    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:351)  
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485)  
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]  
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)  
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)  
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)  
    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:924)  
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:871)  
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)  
    ... 6 more  

    大概就是这个错，搞了好几天，最终找出的原因还是jar包引入的错误，由于各种原因maven在下载jar包的时候并没有下完完全，但是在项目中的引用却不会出错，

修改bug方法：

在eclipse或者idea工具中，运行maven test。eclipse的话右击项目-Run as 可以选择，idea的右侧maven工具栏上级test，便可以在控制台查看出问题的jar包，最直接的办法就是在本地仓库当中删除该jar包所在的目录，然后重新使用maven reimport下载，直到没有jar包的报错，启动项目，OK了！

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