struts 让浏览器提示文件下载，而不是显示文件的内容

struts.xml 方式配置

    <action name="Download" class="xx.action.DownLoad">
           <result type="stream" name="success">
              <param name="inputName">inputStream</param>
              <param name="contentType">application/octet-stream</param>
              <param name="contentDisposition">attachment;filename="xx.jpg"</param>
           </result>
       </action>

struts-convention方式配置

@Results( 
{ 
    @Result(name = "qcCode", type = "stream", params={"contentType", "application/octet-stream","contentDisposition","attachment;filename=qcCode.png","inputName","inputStream"})
})