使用过滤器
 创建 一个实现了 struts 提供的 filter 类
   public class EncodingFilter implements Filter {
 
    public void destroy() {
        // TODO Auto-generated method stub
         
    }
 
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {
         arg0.setCharacterEncoding("utf-8");
         arg1.setCharacterEncoding("utf-8");
         arg2.doFilter(arg0, arg1);
    }
 
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub
         
    }
 
}