import 'dart:convert'; 
import 'package:crypto/crypto.dart';

class SignServices{

  static getSign(json){
    
      List attrKeys=json.keys.toList();
      attrKeys.sort(); //排序  ASCII 字符顺序进行升序排列      
      String str='';
      for(var i=0;i<attrKeys.length;i++){
        str+="${attrKeys[i]}${json[attrKeys[i]]}";
      }           
      return md5.convert(utf8.encode(str)).toString();

  }
}