/**     * 读取文件     *      * @param request     * @param response     * @param path     */    @RequestMapping(value = "/readFile", method = {RequestMethod.POST,RequestMethod.GET})    public void readFile(HttpServletRequest request, HttpServletResponse response, Long id) {        response.reset();        InputStream in = null;        OutputStream output = null;　　　　　try {            //调用ServletOutputStream或者Writer之前有效。            //当使用的缓存已满时，容器必须立刻刷新把缓存的内容发送到客户端，如果这是第一个被发送到客户端的数据，那么response也会被认为是已提交            File file = new File(ctxPath + File.separator + fileName);                        //输出文件流            if (file.exists()) {                output = response.getOutputStream();                in = new FileInputStream(file);                byte tmp[] = new byte[256];                int i = 0;                while ((i = in.read(tmp)) != -1) {                    output.write(tmp, 0, i);                }                output.flush();            }                } catch (Exception e) {            e.printStackTrace();        } finally {            try {                if (null != in) {                    in.close();                }                if (null != output) {                    output.close();                }            } catch (Exception e) {                e.printStackTrace();            }        }    }