七牛上传获取 uptoken,我是在springMVC的controller中获取token的 一直提示 找不到Auth类

1、七牛上传获取 uptoken,我是在springMVC的controller中获取token的 一直提示 找不到Auth类，但是使用main方法 没问题。
2、代码如下：
@Controller
public class UploadController{

 private static Log logger=LogFactory.getLog(UploadController.class);

  public String getUpToken(){
    //要上传的空间
      String bucketname = "huling-alert";
    //秘钥配置
      Auth auth = Auth.create("yPlDLFHNcjx6VAHpRRZI4_OAq83SGGiahZeDCWbu", "VphecIM52thbRdePWvKlHTg0eqmjzndgcFeD7-cJ");
      return auth.uploadToken(bucketname);
  }
  
  
 @RequestMapping(value = "/now/uptoken", method = RequestMethod.GET)
  @ResponseBody
  public String generateToken(HttpServletRequest req, HttpServletResponse resp){
     
     String uptoken = getUpToken();
      JSONObject token = new JSONObject();
      token.put("uptoken", uptoken);
      return token.toString();
  }

}