Nested JSON objects within JSON array

Question

I'm trying to parse the nested JSON object within the JSON array. I'm not sure how to go about accessing all the objects and the Keys and Values within the nested JSON objects in a generic way.

     {
        "flights": [
        {
            "ident": "AWI4207",
            "faFlightID": "AWI4207-1505297520-schedule-0000",
            "origin": {
                "code": "KORF",
                "city": "Norfolk, VA",
                "alternate_ident": "",
                "airport_name": "Norfolk Intl"
            },
            "destination": {
                "code": "KPHL",
                "city": "Philadelphia, PA",
                "alternate_ident": "",
                "airport_name": "Philadelphia Intl"
            },
            "filed_ete": 2400,
            "filed_departure_time": {
                "epoch": 1505470320,
                "tz": "EDT",
                "dow": "Friday",
                "time": "06:12AM",
                "date": "15/09/2017",
                "localtime": 1505455920
            },
        }
      ]
    }

Here's what i've done so far.

JSONParser parser = new JSONParser();
JSONObject object = (JSONObject) parser.parse(new FileReader("PathToFile.json"));

JSONArray jsonArray = (JSONArray) object.get("flights");
Iterator<Object> eventJSONIterator = jsonArray.iterator();

while (eventJSONIterator.hasNext()) {
  JSONObject jsonEvent = (JSONObject) eventJSONIterator.next();
  System.out.println(jsonEvent.toString());
}

I'm able to access the objects but not the sub-objects separately. Is there a way to iterate through the object in the "flights" array and know somehow if i've encountered a JSON Object (e.g. "origin") again and loop inside it? Rather than doing the following

JSONObject mainObject = (JSONObject) jsonArray.get(0);

JSONObject origin = (JSONObject) mainObject.get("origin");
JSONObject destination = (JSONObject) mainObject.get("destination");
JSONObject filed_departure_time = (JSONObject) mainObject.get("filed_departure_time");

Also, i want to access the keys as origin_code, origin_city and destination_code, destination_city etc. so as to know which object it belonged to.

I suppose this is Java. Please tag your question as such.

trincot
– trincot

2017-09-16 09:52:58 +00:00
Commented Sep 16, 2017 at 9:52 — trincot
– trincot, Commented Sep 16, 2017 at 9:52

Shriyansh Gautam · Accepted Answer · 2017-09-16 11:59:47Z

2

You can do this

JSONParser parser = new JSONParser();
    JSONObject object = (JSONObject) parser.parse(new FileReader("PathToFile.json"));

    JSONArray jsonArray = (JSONArray) object.get("flights");
    for(int i=0;i<jsonArray.size();i++){
        JSONObject flightJSON = jsonArray.getJSONObject(i);
        JSONObject origin = flightJSON.getJSONObject("origin");
        String code = origin.get("code");
        String city = origin.get("city");
        String alternate_ident = origin.get("alternate_ident");
        String airport_name = origin.get("airport_name");
        //Similaryly for these
        JSONObject destination = flightJSON.getJSONObject("destination");
        JSONObject filed_departure_time = flightJSON.getJSONObject("filed_departure_time");


    }

You need to know the structure to parse it but if you don't know whether it is array,object or other entities, you can try

  Object object = json.get("key");
  if (object instanceof JSONArray) {
   // JSONObject
   jsonArray = (JSONArray)object;
  }else if (object instanceof JSONObject) {
    // JSONArray
    jsonObject = (JSONObject)object;
  }else {
   // String or Integer etc.
 }

edited Sep 16, 2017 at 11:59

answered Sep 16, 2017 at 9:03

Shriyansh Gautam

1,0821 gold badge7 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

8 Comments

Alohamora153 Over a year ago

jsonArray.length() inside the for loop shows me error for some reason. "The method length() is undefined for the type JSONArray"

Shriyansh Gautam Over a year ago

have you imported org.json.JSONArray for JSONArray?

Shriyansh Gautam Over a year ago

see the updated answer jsonArray.size() for your case

Alohamora153 Over a year ago

Yes. I was using org.json.simple.JSONArray. It worked after making a few adjustments. But i still want to know if there's any way of identifying a JSON object within JSON object without having to look at the JSON array.

Shriyansh Gautam Over a year ago

if you don't know the structure then there is no what for rest you can see the updated answer

|

Collectives™ on Stack Overflow

Nested JSON objects within JSON array

1 Answer 1

8 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

8 Comments

Your Answer

Sign up or log in

Post as a guest

Related