Jsonarray traversal

One . Requirements describe ：

Need to put json Array JSONArray Object to traverse 、 Convert to List object

Two . Demand analysis ：

1. The first thing I think of is direct traversal , adopt JSONObject Object to get the specified k Of v value

for (JSONObject a : jsonArray){

   list.add(a.get("k"))
}

But compilation exception , The display traversal object must be Object object , I was confused at that time ,json Array is not put json..

2. View source code ：

What we achieve is List<Object> Method , drunk .....

3. Try forced transformation JSONObject, Report errors ：

for (JSONObject a : jsonArray){
   JSONObject x = (JSONObject) a
   list.add(x.get("k"))
}

3、 ... and . resolvent ：

Object You need to turn first JSON, Then you can turn JSONObject:  

JSON.toJSON

for (JSONObject a : jsonArray){
   JSONObject x = (JSONObject) JSON.toJSON(a)
   list.add(x.get("k"))
}

perhaps ：

List list = conditions.stream().map(obj -> {
            JSONObject jsonObj = (JSONObject) JSON.toJSON(obj);
            return jsonObj.getString("status");
        }).collect(Collectors.toList());