使用struts2 进行文件下载时文件名变成路径了

Question

//xml
    <action name="downfile" class="com.ipvr.edu.Action.PersonalFileAction" method="download">
          <result type="stream">
            <param name="bufferSize">2048</param>
            <param name="contentDisposition">attachment;fileFileName=${fileFileName}</param> 
            <param name="contentCharSet">UTF-8</param>
          </result>
          <result name="error" type="redirect">error.html</result>
   </action>
 //action
     String fid=request.getParameter("fid");
         if(fid==null){
            return Action.ERROR;
      }else{
            PersonalFile file = new PersonalFileService().getFileByFid(fid);
            String filePath = file.getFilePath();
            contentType = file.getFileType();
            contentDisposition = "attachment;filename=" + filePath;
            File files = new File(filePath);
            inputStream = new FileInputStream(files);
            this.fileFileName=file.getFileName();
            contentLength = inputStream.available();
            return Action.SUCCESS;
         

}
//下载后的文件名称是这样的 ----C--apache-tomcat-7.0.70-webapps-Tx4.0-files-TeamFile-20170313003106337.sql---