Gson 转map long出现1.490341044E12 ，而int出现1.0

 String json = "{'expiretime1':1490341044000,'expiretime2':18813140601,'cost':1}";
Gson gson = new Gson();
Map<String, Object> resultMap = gson.fromJson(json, new TypeToken<Map<String, Object>>() {}.getType());
System.out.println("result:" + resultMap);

运行结果：
result:{expiretime1=1.490341044E12, expiretime2=1.8813140601E10, cost=1.0}
期望结果：
result:{expiretime1=1490341044000, expiretime2=18813140601, cost=1}
怎么解决呢？