有序解析
方法1：gson

LinkedHashMap<String, Object> map1= new LinkedHashMap<>();
        map1.put("a",1);
        map1.put("b","B");
        Gson gson = new GsonBuilder().enableComplexMapKeySerialization().create();
String signdata = gson.toJson(map1);
        

方法2：fastjson

String s = JSON.toJSONString(map1);
#有序转实体
Op op = JSON.parseObject(s, Op.class, Feature.OrderedField);
#有序转map
HashMap map = JSON.parseObject(s, LinkedHashMap.class, Feature.OrderedField);