Starting Tomcat v7.0 Server at localhost' has encountered a problem

今天在启动一个简单的java web项目时，这个出现了这样的情况

然后控制台出现了各种各样的异常，

严重: A child container failed during start  java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/TestSpringMVC]]      at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222)      at java.util.concurrent.FutureTask.get(FutureTask.java:83)      at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)      at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:816)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1575)      at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1565)      at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)      at java.util.concurrent.FutureTask.run(FutureTask.java:138)      at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)      at java.lang.Thread.run(Thread.java:619)  Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/TestSpringMVC]]      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)      ... 7 more  Caused by: java.lang.NoClassDefFoundError: Lorg/apache/commons/logging/Log;      at java.lang.Class.getDeclaredFields0(Native Method)      at java.lang.Class.privateGetDeclaredFields(Class.java:2291)      at java.lang.Class.getDeclaredFields(Class.java:1743)      at org.apache.catalina.util.Introspection.getDeclaredFields(Introspection.java:106)      at org.apache.catalina.startup.WebAnnotationSet.loadFieldsAnnotation(WebAnnotationSet.java:270)      at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:139)      at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:65)      at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:415)      at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:892)      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:5380)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      ... 7 more  Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.Log      at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)      at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)      at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)      ... 21 more  2014-10-24 11:52:23 org.apache.catalina.core.ContainerBase startInternal  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$Sync.innerGet(FutureTask.java:222)      at java.util.concurrent.FutureTask.get(FutureTask.java:83)      at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)      at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:739)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      at org.apache.catalina.startup.Catalina.start(Catalina.java:689)      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)      at java.lang.reflect.Method.invoke(Method.java:597)      at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:321)      at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:455)  Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)      at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1575)      at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1565)      at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)      at java.util.concurrent.FutureTask.run(FutureTask.java:138)      at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)      at java.lang.Thread.run(Thread.java:619)  Caused by: org.apache.catalina.LifecycleException: A child container failed during start      at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1131)      at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:816)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      ... 7 more  2014-10-24 11:52:23 org.apache.catalina.startup.Catalina start  严重: 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:154)      at org.apache.catalina.startup.Catalina.start(Catalina.java:689)      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)      at java.lang.reflect.Method.invoke(Method.java:597)      at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:321)      at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:455)  Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)      at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:739)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      ... 7 more  Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]]      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)      at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      ... 9 more  Caused by: org.apache.catalina.LifecycleException: A child container failed during start      at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1131)      at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)      ... 11 more  

原因：

1.可能是web.xml配置的问题；

2.可能是jar包冲突或缺少jar包；

解决方式：

1.检查web.xml文件是否配置错误；

2.把jar包全部clean，然后一个一个添加，缺少哪个添加哪个，根据错误信息里缺少的jar包逐一添加；

我是两种情况都有，第一种情况时却说servlet-api.jar包，导致类都无法创建。（我前面的博客有介绍）

还有就是我的web.xml由于我的粗心结果导致<servlet-name></servlet-name>中名字的一个字母没写，结果就启动不了了。

注意：jar包可少不可多，少哪个添加哪个；

转自：http://blog.csdn.net/jiangnan2014/article/details/40425383

注意：jar包可少不可多，少哪个添加哪个；