code: public static boolean validateSign(Map<String,String> map,String sign_type,String key){
  		if(map.get("sign") == null){
  			return false;
  		}
  		return map.get("sign").equals(generateSign(map,sign_type,key));
  	}
docs: mch 支付、代扣API调用签名验证
  
  @param map 参与签名的参数
  @param sign_type HMAC-SHA256 或 MD5
  @param key mch key
  @return boolean