关于java web项目中web.xml文件的配置问题

[qq_33358583]

在web.xml中，刚开始只有一个servlet标签和一个servlet-mapping标签，在加了另一个servlet标签和servlet-mapping标签后，Tomcat7就启动不了。如下图：

[qq_33358583]

删掉之后就能正常启动

[十八道胡同]

引用 7 楼 qq_33358583 的回复:

不是这个问题，解决了

怎么解决的？

[尼坤神]

mapping地址写的有问题吧

[onOneLight]

分享一下错误答案

[realchenzhuo]

麻烦楼主说一下解决过程和方法呀，以便后人遇到类似的错误可以参考参考

[农夫阿才]

xml文件写的就有问题

[nayi_224]

别发图片！把xml跟控制台信息发出来。

[qq_33358583]

tomcat7.0版本的，添加servlet的时候一定要手写，拷贝自己上面的也不行，还有有些包不仅要导入到自己项目里的lib里面，还要加到tomcat的lib文件夹下，比如我这个问题，就是我没有把上传文件的两个包加到tomcat的lib文件夹中导致的。

[鸣鸣Amadues]

应该是没有按照格式写。 现在servlet可以用注解写了，不用在web.xml里配置了，不过我不知道tomcat7是不是支持。

[极客星云]

展开Detail 给我们看下报错信息，或者把日志控制台报错信息贴出来，不然没法定位Bug

[yuji_tt]

mapping格式不对

[qq_33358583]

一月 02, 2019 12:31:23 下午 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:162) at org.apache.catalina.startup.Catalina.start(Catalina.java:710) 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:162) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:758) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 7 more Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:444) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 9 more Caused by: org.apache.catalina.LifecycleException: A child container failed during start at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1254) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 11 more Caused by: 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:1243) ... 13 more Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1707) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1697) 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:1254) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:819) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 6 more Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/UseSC]] 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:1243) ... 8 more Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/UseSC]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) ... 6 more Caused by: java.lang.NoClassDefFoundError: org/apache/commons/fileupload/FileUploadException at java.lang.Class.getDeclaredFields0(Native Method) at java.lang.Class.privateGetDeclaredFields(Unknown Source) at java.lang.Class.getDeclaredFields(Unknown Source) 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:138) at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:70) at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:417) at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:884) at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:388) 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:5566) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) ... 6 more Caused by: java.lang.ClassNotFoundException: org.apache.commons.fileupload.FileUploadException at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1945) at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1788) ... 20 more

[qq_33358583]

[十八道胡同]

参考 https://www.cnblogs.com/yidan621/p/5252075.html

[qq_33358583]

不是这个问题，解决了

[千里共良辰]

这个报错很大关系和对外访问路径有关

[maradona1984]

Caused by: java.lang.ClassNotFoundException: org.apache.commons.fileupload.FileUploadException

难道不是这个?
目测他的servlet里用到了某个第三方jar的东西,但初始化抛FileUploadException异常,但由于版本不对或者jar没依赖FileUploadException又不存在,所以就java.lang.ClassNotFoundException

[IT界的草根]

可以使用在注解型配置，不用xml配置

[weixin_44286118]

我管你，反正我解决了