HTTP Status 404 - There is no Action mapped for namespace / and action name first.
type Status report
message There is no Action mapped for namespace / and action name first.
description The requested resource is not available.
Apache Tomcat/6.0.37
解决：
1.struts.xml文件名出现出错：如：sturts.xml拼写错误，struts2.xml理解错误；
2.struts.xml文件放置位置出错，应该放在src目录下；
3.struts.xml文件内容出错