struts2入门的HelloWorld报错！

启动tomcat，直接报错：

严重: ********** FATAL ERROR STARTING UP STRUTS-SPRING INTEGRATION **********
Looks like the Spring listener was not configured for your web app!
Nothing will work until WebApplicationContextUtils returns a valid ApplicationContext.
You might need to add the following to web.xml:
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
2010-7-6 17:43:30 com.opensymphony.xwork2.util.logging.commons.CommonsLogger error
严重: Dispatcher initialization failed
java.lang.NullPointerException
at com.opensymphony.xwork2.spring.SpringObjectFactory.getClassInstance(SpringObjectFactory.java:209)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.verifyResultType(XmlConfigurationProvider.java:519)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addResultTypes(XmlConfigurationProvider.java:490)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:446)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:264)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:111)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:193)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:55)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:374)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:418)
at org.apache.struts2.dispatcher.FilterDispatcher.init(FilterDispatcher.java:190)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:295)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3838)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4488)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:546)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1041)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:964)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:502)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1277)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:321)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:785)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:519)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:581)
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:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)

说是什么spring文件初始化不了。
然后我按照上述提示，添加了
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

重启tomcat，就报了一个找不到spring的applicationcontext.xml文件的错误。

问题已经解决了，网上找了资料。
全部包都引入是个错误，只需要简单的6个包！就足够了。
本来，网上几乎所有资料都说，需要5个基本包。
我也尝试过仅仅导入5个包。发现是不行的。
事实上的确是6个，不是5个。

网上资料如下：

Struts2.1.x终于推出正式版了，下载后按照Struts 2.0.14版进行配置，抛出异常说无法装载 (org.apache.struts2.dispatcher.multipart.MultiPartRequest)，异常信息提示摘不到 org.apache.commons.fileupload.RequestContext类，搜索struts2.1.6带的所有jar包，发现RequestContext类并不在struts2-core-2.1.6.jar 中，在commons-fileupload-1.2.1.jar包中，之前struts2.0.14并不需要此包，只有在要用到上传组件的时候才需要。可能是struts2.1.6对文件上传功能的改进。因此要想正常使用struts2.1.6，至少需要如下6 个jar包：
struts2-core-2.1.6.jar
freemarker-2.3.13.jar
commons-logging-1.0.4.jar
ognl-2.6.11.jar
xwork-2.1.2.jar
commons-fileupload-1.2.1.jar