为什么我的struts编码过滤器不起作用?

Filter类:
package com.basemodel.filters;import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;public class CharacterEncodingFilter implements Filter {
protected String encoding = null; protected FilterConfig filterConfig = null; protected boolean ignore = true; public void init(FilterConfig filterConfig) throws ServletException {
this.filterConfig = filterConfig;
this.encoding = filterConfig.getInitParameter("encoding");
String value = filterConfig.getInitParameter("ignoer");
if (value == null)
this.ignore = true;
else if (value.equalsIgnoreCase("true"))
this.ignore = true;
else if (value.equalsIgnoreCase("yes"))
this.ignore = true;
else
this.ignore = false; } public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
if (this.ignore || (request.getCharacterEncoding() == null)) {
String encoding = selectEncoding(request);
if (encoding != null)
request.setCharacterEncoding(encoding);
}
chain.doFilter(request, response); } public void destroy() {
this.encoding = null;
this.filterConfig = null;
} protected String selectEncoding(ServletRequest request) {
return this.encoding;
}
}
web.xml设置:
<filter>
<description>HTTP请求编码设置过滤器</description>
<filter-name>CharacterEncodingFilter</filter-name>
<filter-class>com.basemodel.filters.CharacterEncodingFilter</filter-class>
<init-param>
<description>编码名称</description>
<param-name>encoding</param-name>
<param-value>UTF8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CharacterEncodingFilter</filter-name>
<servlet-name>/*</servlet-name>
</filter-mapping>

<servlet>
<servlet-name>action</servlet-name>
<servlet-class>
org.apache.struts.action.ActionServlet
</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>
/WEB-INF/struts_config/struts-config.xml,
/WEB-INF/struts_config/a/struts-a-config.xml
</param-value>
</init-param>
<servlet>
页面都是设为UTF-8编码.
请专家帮我!