钉钉免登陆签名

public static String getSign(String ticket, String nonceStr, long timeStamp, String url) throws Exception {  
        String plain = "jsapi_ticket=" + ticket + "&noncestr=" + nonceStr + "×tamp=" + String.valueOf(timeStamp)  
                + "&url=" + url;  
        try {  
            MessageDigest sha1 = MessageDigest.getInstance("SHA-1");    //安全hash算法  
            sha1.reset();  
            sha1.update(plain.getBytes("UTF-8"));                       //根据参数产生hash值  
            return bytesToHex(sha1.digest());  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception(e.getMessage());  
        } catch (UnsupportedEncodingException e) {  
            throw new Exception(e.getMessage());  
        }  


    }  
      
    //将bytes类型的数据转化为16进制类型  
    private static String bytesToHex(byte[] hash) {                    //将字符串转化为16进制的数据  
        Formatter formatter = new Formatter();  
        for (byte b : hash) {  
            formatter.format("%02x", b);  
        }  
        String result = formatter.toString();  
        formatter.close();  
        return result;  
    }
获取的signature和在测试平台上的不一样，请问哪里出问题了，谢谢！