Parsing json object in java, object not found

Question

I'm trying to parse the following (expected) json response to return an array of id

{
 "establishments":[
 {
 "establishment":{
 "id":21,
 "name":"Quick Bites"
 }
 },
 {
 "establishment":{
 "id":16,
 "name":"Casual Dining"
 }
 },
 {
 "establishment":{
 "id":7,
 "name":"Bar"
 }
 },
 {
 "establishment":{
 "id":6,
 "name":"Pub"
 }
 },
 {
 "establishment":{
 "id":5,
 "name":"Lounge"
 }
 },
 {
 "establishment":{
 "id":31,
 "name":"Bakery"
 }
 },
 {
 "establishment":{
 "id":18,
 "name":"Fine Dining"
 }
 },
 {
 "establishment":{
 "id":275,
 "name":"Pizzeria"
 }
 },
 {
 "establishment":{
 "id":1,
 "name":"Caf\u00e9"
 }
 },
 {
 "establishment":{
 "id":24,
 "name":"Deli"
 }
 },
 {
 "establishment":{
 "id":285,
 "name":"Fast Casual"
 }
 },
 {
 "establishment":{
 "id":271,
 "name":"Sandwich Shop"
 }
 },
 {
 "establishment":{
 "id":282,
 "name":"Taqueria"
 }
 },
 {
 "establishment":{
 "id":283,
 "name":"Brewery"
 }
 },
 {
 "establishment":{
 "id":161,
 "name":"Microbrewery"
 }
 },
 {
 "establishment":{
 "id":23,
 "name":"Dessert Parlour"
 }
 },
 {
 "establishment":{
 "id":101,
 "name":"Diner"
 }
 },
 {
 "establishment":{
 "id":286,
 "name":"Coffee Shop"
 }
 },
 {
 "establishment":{
 "id":81,
 "name":"Food Truck"
 }
 },
 {
 "establishment":{
 "id":91,
 "name":"Bistro"
 }
 },
 {
 "establishment":{
 "id":272,
 "name":"Cocktail Bar"
 }
 },
 {
 "establishment":{
 "id":284,
 "name":"Juice Bar"
 }
 },
 {
 "establishment":{
 "id":281,
 "name":"Fast Food"
 }
 },
 {
 "establishment":{
 "id":8,
 "name":"Club"
 }
 },
 {
 "establishment":{
 "id":20,
 "name":"Food Court"
 }
 },
 {
 "establishment":{
 "id":278,
 "name":"Wine Bar"
 }
 }
 ]
}

I'm using the following code:

private static void parseEstablishments (JSONObject r) {
 System.out.println("in parseEstablishments");
 System.out.println(r.length()); 
 JSONArray array = r.getJSONArray("establishment");
 List<String> list = new ArrayList<String>();
 for (int i = 0; i < array.length(); i++) {
 list.add(array.getJSONObject(i).getString("id"));
 }
 System.out.println("done");
}

r.length prints out 1 and r.toString prints out {"encoding":"UTF8"}. I'm also getting the following error: JSONObject["establishment"] not found.

Not really sure what's wrong. Can anyone help? Thanks.

• guillaume girod-vitouchkina: establishments should work instead, after that, go inside
• 1.mkn: @guillaumegirod-vitouchkina what's the syntax for accessing establishments then establishment? sorry, very new at this.
• 1.mkn: @guillaume establishments doesn't work either...

Answer 1

You can't access establishment if you didn't go into establishments. For example we have class A which has field with class B. You can't access B until you get A. Another example: When you eat orange you first eat what's inside or remove the skin?

You might also consider checking is your JSON what you expect it to be.

• 1.mkn: how can I check my json? when it print it out with toString() I get the UTF8 code though I don't think that's correct. If i convert the response to a string buffer > toString() and print that it's the response that I expect it to be. How do I go into establishments? sorry, pretty new at this.
• Mibac: Try something like string == expectedString.
• 1.mkn: the json response > String Buffer isn't the same as the json response itself...I don't understand why this is or what I should do about.

Answer 2

Hope this code snippet helps you..!!

private static void parseEstablishments (JSONObject r) throws JSONException {
 System.out.println("in parseEstablishments");
 System.out.println(r.length()); 
 JSONArray array = r.getJSONArray("establishments");
 List<String> list = new ArrayList<String>();
 for (int i = 0; i < array.length(); i++) {
 JSONObject establishmentObj=new JSONObject(array.get(i).toString());
 list.add(String.valueOf(new JSONObject(establishmentObj.get("establishment").toString()).get("id")));
 }
 System.out.println("List Of Ids:"+list);
 System.out.println("done");
 }

• Sanjeev H: As @mibac said first need to access establishments then loop through all establishment and get ids, before using this code think about performance(object creation in loop and toString operation..!!)

Answer 3

First of all , it should be

JSONArray array = r.getJSONArray("establishments");

The JSON array key is establishments with the s

Then because your object is nested in another object :

 {
 "establishment":{
 "id":21,
 "name":"Quick Bites"
 }
 }

Your loop needs to change :

for (int i = 0; i < array.length(); i++) {
 JSONObject establishmentObj=array.getJSONObject(i)
 .getJSONObject("establishment");
 list.add(establishmentObj.getString("id"));
}

• 1.mkn: my code doesn't even make it to the loop, event after changing the array key to "establishments" with the s it still says "[establishments] not found."
• meda: Then something is else is not correct, I suggest you log r.toString()