Java fastJson 和 gson 在序列化时遇到的坑

先上例子：

 private static Gson gson = new GsonBuilder().serializeNulls().create();
    public static void main(String[] args) {
        Test test = new Test();
        test.test();
    }
    
    public void test() {
        List<DepartGroup> groups = new ArrayList<DepartGroup>();
        DepartGroup runningGroup = new DepartGroup();
        runningGroup.eTime = "00:00";
        runningGroup.fTime = "40:00";
        groups.add(runningGroup);
        
        String jsonResult = gson.toJson(groups);
        System.out.println(jsonResult);
        jsonResult = JSON.toJSONString(runningGroup);
        System.out.println(jsonResult);
    }
    
    class DepartGroup {
        private GroupTag tag;
        private String fTime;
        private String eTime;
    }

输出时这样的：

[{"tag":null,"fTime":"40:00","eTime":"00:00"}]
{}

gson在序列化时，不管属性是否私有，都可以序列化成功，

但是fastjson则不行，需要添加get方法或者改为public才行