Struts2获取下载文件大小

<result name="success" type="stream">

        <param name="contentType">video/x-msvideo</param>
        <param name="inputName">targetFile</param>
        <param name="contentDisposition">
               attachment;filename="${contentDisposition}"
        </param>
        <!-- 设置缓冲大小为2M -->
        <param name="bufferSize">2097152</param>
        <param name="contentLength">${contentLength}</param>

</result>

 

File f = new File(ServletActionContext.getRequest().getRealPath("upload/tdm")+"/"+this.tdm.getTdmFile());
        this.contentLength = f.length()+"";
        f = null;