Struts实现文件下载

1.struts 1
通过struts实现文件下载有两种方式，一种是继承DownloadAction，一种是读取文件流然后output到response里面。
? 1.继承DownloadAction，需要重写getStreamInfo方法，返回StreamInfo，DownloadAction有两个StreamInfo，FileStreamInfo和ResourceStreamInfo。
? 例子:

public ActionForward download(ActionMapping mapping, ActionForm form,                HttpServletRequest request, HttpServletResponse response) {            try           {                String path = new String(rootFolder +request.getParameter("path"));                File file = new File(path);                String filename = file.getName();                                //取得文件的扩展名ext                String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();                                InputStream fis = new BufferedInputStream(new FileInputStream(path));                byte[] buffer = new byte[fis.available()];                fis.read(buffer);                fis.close();                                response.reset();                response.addHeader("Content-Disposition", "attachment;filename="+new String(filename.getBytes()));                response.addHeader("Content-Length", ""+file.length()); //设置返回的文件类型                OutputStream toClient = new BufferedOutputStream(response.getOutputStream()); //得到向客户端输出二进制数据的对象                //根据扩展名声称客户端浏览器mime类型                if(ext.equals("DOC"))                    response.setContentType("application/msword");                else                   response.setContentType("application/octet-stream"); //设置返回的文件类型                toClient.write(buffer); //输出数据                toClient.flush();                toClient.close();                }                catch(IOException ex){                    ex.printStackTrace();                }                return null;            }