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;
}