Maven Scrop分析

先抛出来问题吧：

刚到一个新公司，给了一个基本的框架，使用tomcat启动website
时候，抛出了一个错误：

严重: A child container failed during startjava.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[]]    at java.util.concurrent.FutureTask.report(FutureTask.java:122)    at java.util.concurrent.FutureTask.get(FutureTask.java:188)    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:800)    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)    at java.util.concurrent.FutureTask.run(FutureTask.java:262)    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)    at java.lang.Thread.run(Thread.java:745)Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[]]    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)    ... 6 moreCaused by: java.lang.ClassCastException: org.springframework.web.SpringServletContainerInitializer cannot be cast to javax.servlet.ServletContainerInitializer    at org.apache.catalina.startup.ContextConfig.getServletContainerInitializer(ContextConfig.java:1670)    at org.apache.catalina.startup.ContextConfig.getServletContainerInitializers(ContextConfig.java:1652)    at org.apache.catalina.startup.ContextConfig.processServletContainerInitializers(ContextConfig.java:1562)    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1270)    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:878)    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:376)    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5322)    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)    ... 6 more四月 23, 2016 1:04:49 上午 org.apache.catalina.core.ContainerBase startInternal严重: A child container failed during startjava.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost]]    at java.util.concurrent.FutureTask.report(FutureTask.java:122)    at java.util.concurrent.FutureTask.get(FutureTask.java:188)    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)    at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:302)    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:732)    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)    at org.apache.catalina.startup.Tomcat.start(Tomcat.java:341)    at org.apache.tomcat.maven.plugin.tomcat7.run.AbstractRunMojo.startContainer(AbstractRunMojo.java:1238)    at org.apache.tomcat.maven.plugin.tomcat7.run.AbstractRunMojo.execute(AbstractRunMojo.java:592)    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)    at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)    at java.lang.reflect.Method.invoke(Method.java:606)    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)    at org.codehaus.classworlds.Launcher.main(Launcher.java:47)Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost]]    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)    at java.util.concurrent.FutureTask.run(FutureTask.java:262)    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)    at java.lang.Thread.run(Thread.java:745)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:800)    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)    ... 6 more

从网上查找到到的原因为：
A better servlet 3.0 api dependency entry in pom is available here - https://github.com/SpringSource/greenhouse/tree/servlet3, you should also mark the scope as provided, otherwise the jar will be included in your final war which will interfere with the jar provided by the container which is what seems to be happening in your case.
大致的翻译如下：你应该标记scope为provided，否则这个jar包将包含在你最后生成的war包中，可能影响容器提供的jar包。
照着做之后果断可以，但还是想了解下maven的scope的作用

compile：编译范围

compile是默认的范围；如果没有提供一个范围，编译范围依赖在所有的classpath 中可用，同时它们也会被打包。而且这些dependency会传递到依赖的项目中。

provided：已提供范围

provided 明了dependency 由JDK或者容器提供。例如如果开发了一个web 应用，可能在编译 classpath 中需要可用的Servlet API 来编译一个servlet，但是你不会想要在打包好的WAR 中包含这个Servlet API；这Servlet API JAR 由你的应用服务器或者servlet容器提供。已提供范围的依赖在编译classpath （不是运行时）可用。它们不是传递性的也不会被打包。

javax.servlet.jsp
jsp-api
2.1
provided

runtime：运行时范围

runtime 依赖在运行和测试系统的时候需要，但在编译的时候不需要。比如可能在编译的时候只需要JDBC API JAR，而只有在运行的时候才需要JDBC驱动实现。

test：测试范围

test范围依赖 在一般的编译和运行时都不需要，它们只有在测试编译和测试运行阶段可用。

junit
junit
4.11
test

system：系统范围

system范围依赖与provided 类似，但是你必须显式的提供一个对于本地系统中JAR 文件的路径。这么做是为了允许基于本地对象编译，而这些对象是系统类库的一部分。这样的构件应该是一直可用的，Maven 也不会在仓库中去寻找它。如果你将一个依赖范围设置成系统范围，你必须同时提供一个 systemPath 元素。注意该范围是不推荐使用的（你应该一直尽量去从公共或定制的 Maven 仓库中引用依赖）。

引用：

http://stackoverflow.com/questions/15328363/springservletcontainerinitializer-cannot-be-cast-to-javax-servlet-servletcontain
http://blog.csdn.net/daihui05/article/details/7476976