map判断是否存在某个key，以及遍历jsonobject

if (filter.containsKey("nodeData")) {
            JSONObject jsonObject = (JSONObject) filter.get("nodeData");
            Iterator iterator = jsonObject.keySet().iterator();
            while (iterator.hasNext()){
                String next = (String) iterator.next();
                Object o = jsonObject.get(next);
                filter.put(next,o);
            }
        }