使用servlet3.0提供的API来进行文件的上传操作

　　@RequestMapping(value = "/add", method = RequestMethod.POST)
　　@ResponseBody
    public String addFile(HttpServletRequest request) throws IOException, ServletException {
        request.setCharacterEncoding("UTF-8");
        Part filePart = request.getPart("file");
        String fileName = filePart.getSubmittedFileName();//文件名
        long size = filePart.getSize();//文件大小
        String contentType = filePart.getContentType();//文件的MIME类型
        byte[] data = new byte[(int) size];
        filePart.getInputStream().read(data);//以InputStream表示的文件流信息
        String fileUUID = this.fileService.addFile(fileName, contentType, size, data);
        return fileUUID;
    }