if let file = AVUser.current()?.object(forKey: "profileIm") as? AVFile{
        file.getDataInBackground({ (data:Data?, error:Error?) in
            if error==nil{
                self.profileImage.image = UIImage(data: data!)
            }else{
                print(error!)
            }
        }, progressBlock: { (progress:Int) in
            //progress is a value from 0~100
        })
    }

报错：

Error Domain=AVOS Cloud Error Domain Code=149 "file checksum incorrect" UserInfo={error=file checksum incorrect, NSLocalizedDescription=file checksum incorrect, code=149}

问题解决了。不用AVUser.current()来取得当前用户的AVObject而使用AVQuery的话就一切正常。