Web应用文件结构：
/tutorial/
/tutorial/META-INF/
/tutorial/WEB-INF/
/tutorial/WEB-INF/classes/
/tutorial/WEB-INF/lib/
/tutorial/WEB-INF/lib/minimum JARs + any plugin JARs + plugin dependencies
/tutorial/WEB-INF/web.xml
基本类库及配置文件：
| Filename |
Description |
| struts2-core.jar |
Framework library itself, found in distribution root directory |
| xwork.jar |
XWork 2 library on which Struts 2 is built (version 2.0 or later) |
| ognl.jar |
Object Graph Navigation Language (OGNL), the expression language used throughout the framework |
| freemarker.jar |
All UI tag templates are written in Freemarker (also a good option for your own views) |
| commons-logging.jar |
Commons logging, which the framework uses to support transparently logging to either Log4J or JDK 1.4+ |
| web.xml |
Java web application configuration file that defines the filters (and other components) for your web application |
| struts.xml |
Framework configuration file that defines the actions, results, and interceptors for your application |