Struts2 configuration constants way

struts2 configuration constants there are 3 ways

　　1, in the configuration file in the configuration Struts2.xml

　　　　例如:<constant name="struts.action.extension" value="do" />

　　2, in the configuration in struts.properties

　　　　E.g:

 

 

　　3, configured in the web.xml

 

　　　　E.g: