我开始学习 Struts 2。我偶然发现了这段代码：
web.xml
...some other codes...
<filter>
<filter-name>MyFilter</filter-name>
<display-name>MyFilter</display-name>
<filter-class>com.xxx.yyy.zzz.MyFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>MyFilter</filter-name>
<servlet-name>MyAction</servlet-name>
</filter-mapping>
<listener>
<listener-class>com.xxx.yyy.StrutsListener</listener-class>
</listener>
<servlet>
<servlet-name>MyAction</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>paramName1param-name>
<param-value>paramVal1</param-value>
</init-param>
<init-param>
<param-name>paramName2</param-name>
<param-value>paramVal2</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
...some other codes...
我的问题在这部分
<filter-mapping>
<filter-name>MyFilter</filter-name>
<servlet-name>MyAction</servlet-name>
</filter-mapping>
为什么它是一个被映射到<filter-mapping>标签内的 servlet？这种映射意味着什么？还有，有什么作用<listener>？感谢您的回复。