Struts2 configuration file meaning of various tags

Recently learning Struts2, in the configuration file encountered a lot of tags, different meanings. In order to facilitate learning, then the various labels of the writing and meaning summarized as follows: (update at any time)

<struts>

<!--turn on Use development mode (you can debug a program without restarting the service after changing the Struts.xml file), with detailed error hints. The Ps:value value of false is to turn off development mode (?), which is true to turn on development mode--
<constant name= "Struts.devmode" value= "true"/>
<!--Specify global internationalized resource Files--
<constant name= "struts.custom.i18n.resources" value= "mess"/>
<!--Specify the character set used for internationalized encoding--
<constant name= "struts.i18n.encoding" value= "UTF-8"/>
<!--all action definitions should be placed under the package--
<package name= "Unique, indicates that the name of the package" namespace= "represents the namespace, as part of the access path" extends= "designates the contract, where Struts-default defines the core functions of struts" >
<action name= "Login" class= "Com.bell.action.LoginAction" >
<!--define a mapping between three logical views and physical resources--
<result name= "Input" >/login.jsp</result>
<result name= "Error" >/error.jsp</result>
<result name= "Success" >/welcome.jsp</result>
</action>
</package>
</struts>

Struts2 configuration file meaning of various tags