web.xml之Filter配置

注意事项：
1，自定义Filter配置filter-mapping时，必须放到struts2即StrutsPrepareAndExecuteFilter或FilterDispatcher上方，否则无效。

实例：一个Filter配置多个Mapping

<filter>
    <filter-name>struts2</filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>struts2</filter-name>
    <url-pattern>*.action</url-pattern>
</filter-mapping>
<filter-mapping>
    <filter-name>struts2</filter-name>
    <url-pattern>*.jsp</url-pattern>
</filter-mapping>