java 使用流下载文件代码详解编程语言

    public HttpServletResponse download(String path, HttpServletResponse response) {   
        try {   
            // path是指欲下载的文件的路径。   
            File file = new File(path);   
            // 取得文件名。   
            String filename = file.getName();   
            // 取得文件的后缀名。   
            String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();   
       
            // 以流的形式下载文件。   
            InputStream fis = new BufferedInputStream(new FileInputStream(path));   
            byte[] buffer = new byte[fis.available()];   
            fis.read(buffer);   
            fis.close();   
            // 清空response   
            response.reset();   
            // 设置response的Header   
            response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));   
            response.addHeader("Content-Length", "" + file.length());   
            OutputStream toClient = new BufferedOutputStream(response.getOutputStream());   
            response.setContentType("application/octet-stream");   
            toClient.write(buffer);   
            toClient.flush();   
            toClient.close();   
        } catch (IOException ex) {   
            ex.printStackTrace();   
        }   
        return response;   
    }