如何在spring mvc+maven项目中获取web上下文路径?

public static File upload(MultipartFile file, HttpServletRequest request, boolean file_name, String upload_folder) {
        String filename = null;
        File serverFile = null;
        try {
            String applicationpath = request.getServletContext().getRealPath("");
            filename = file.getOriginalFilename();
            byte[] bytes = file.getBytes();
            String rootPath = applicationpath;
            File dir = new File(rootPath + File.separator + upload_folder);
            if (!dir.exists())
                dir.mkdirs();
            serverFile = new File(dir.getAbsolutePath() + File.separator + filename);
            BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(serverFile));
            stream.write(bytes);
            stream.close();
            return serverFile;
        } catch (Exception e) {
            serverFile = null;
        }
        return serverFile;
    }