strust1.2 文件下载问题

代码:
public class DownAction extends DownloadAction { @Override
protected StreamInfo getStreamInfo(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
//response.setContentType("application/x-download");  
String name= request.getParameter("fileName");
String fileName = new String(name.getBytes("gbk"),"ISO-8859-1" );
    response.addHeader("Content-Disposition","attachment;filename=" +fileName);
    String contentType = "application/x-download";
    String foldpath= request.getSession().getServletContext().getRealPath("/file");
    File file  = new File(foldpath+"/"+name);
    return new FileStreamInfo("", file);
}}异常:
2009-11-18 13:41:08 org.apache.struts.action.RequestProcessor processException
警告: Unhandled Exception thrown: class org.apache.catalina.connector.ClientAbortException