spring java 获取webapp下文件路径

    @RequestMapping("/act/worldcup_schedule_time/imgdownload")    @ResponseBody    public String scheduleDownload(HttpServletRequest request, HttpServletResponse response, HttpSession session) {        response.setCharacterEncoding("UTF-8");        String downLoadName = "worldcup.jpg";        InputStream input = null;        try {            request.setCharacterEncoding("UTF-8");            //获取文件的路径//            String url = session.getServletContext().getRealPath("/") + "resources\\images\\act\\worldcup_merge\\worldcup720.png";            String url = session.getServletContext().getRealPath("/") + "resources/images/act/worldcup_merge/worldcup720.png";            System.out.println(url);            File file = new File(url);            input = FileUtils.openInputStream(file);            byte[] data = IOUtils.toByteArray(input);            //System.out.println("文件名:"+downLoadName);            response.reset();            //设置响应的报头信息(中文问题解决办法)            response.setHeader("content-disposition", "attachment;fileName=" + URLEncoder.encode(downLoadName, "UTF-8"));            response.addHeader("Content-Length", "" + data.length);            response.setContentType("image/png; charset=UTF-8");            IOUtils.write(data, response.getOutputStream());        } catch (Exception e) {            logger.error("下载图片出错");            if (input != null) {                IOUtils.closeQuietly(input);            }        }        return null;    }