extjs file upload & spring mvc

UploadController.java

	@RequestMapping(value = "/upload", method = RequestMethod.POST, produces = MediaType.TEXT_HTML_VALUE)
	@ResponseBody
	public String upload(@RequestParam("file") MultipartFile file, String name, String message) throws Exception
	{
		Map<String, Object> resp = Maps.newHashMap();

		FileCopyUtils.copy(file.getBytes(), new File('filename'));

		resp.put("success", true);
		resp.put("msg", "upload success.");

		return JSONObject.toJSONString(resp);
	}

extjs上传，response不支持applacation/json，需要设置为text/html。