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;
    }