struts2.1.6中文乱码的疑惑

近期把项目从struts2.0 升级到struts2.1.6，在不加上encodingFilter的情况下，无论怎么设置struts.locale和struts.i18n.encoding，都会中文乱码，加上encodingFilter才没事，不知道这是为什么？希望大虾给予解答
我的web.xml配置

<filter>
	    <filter-name>encodingFilter</filter-name>
	    <filter-class>
	        org.springframework.web.filter.CharacterEncodingFilter</filter-class>
	    <init-param>
	        <param-name>encoding</param-name>
	        <param-value>GBK</param-value>
	    </init-param>
	    <init-param>
	        <param-name>forceEncoding</param-name>
	        <param-value>true</param-value>
	    </init-param>
	</filter>
	<filter-mapping>
		<filter-name>encodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	
	<filter>
		<filter-name>struts2-prepare</filter-name>
		<filter-class>
			org.apache.struts2.dispatcher.ng.filter.StrutsPrepareFilter
		</filter-class>
		<init-param>
			<param-name>actionPackages</param-name>
			<param-value>com.ywlqi.mxq.action</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>struts2-prepare</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	
	<filter>
		<filter-name>struts2-execute</filter-name>
		<filter-class>
			org.apache.struts2.dispatcher.ng.filter.StrutsExecuteFilter
		</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>struts2-execute</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>