How to retrieve values in an array of values from a JSON string in Java

Question

Given the following JSON string returned:

String s = "{"errorCode":0,"result":"Processed","trips":[{"tripDestination":"Vancouver","tripStartTime":"07:41"},{"tripDestination":"Montreal","tripStartTime":"08:04"}]}";

I can easily get errorCode and result with something like:

JSONObject jObject;
jObject = new JSONObject(s);

String result = jObject.getString("result");
Log.v("JSON Result", result);

But I do I get to tripDestiation values, knowing it's an array of values within the JSON string?

Json-simple is a simple toolkil for converting Json code to Java code — AurA
– AurA, Commented Apr 20, 2012 at 12:43

Marko Topolnik · Accepted Answer · 2012-04-20 12:43:52Z

1

jObject.getJSONArray("trips").getJSONObject(0).getString("tripDestination");

answered Apr 20, 2012 at 12:43

Marko Topolnik

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Comments

Matty K · Accepted Answer · 2012-04-20 12:46:50Z

1

You probably want the getJSONArray() method.

See: http://www.json.org/javadoc/org/json/JSONObject.html#getJSONArray(java.lang.String)

Edit: I would use something like:

ArrayList<String> destinations = new ArrayList<String>();
JSONArray trips = jObject.getJSONArray("trips");
for (int i = 0; i < trips.length(); i++) {
    destinations.add(trips.getJSONObject(i).getString("tripDestination"));
}

edited Apr 20, 2012 at 12:46

answered Apr 20, 2012 at 12:41

Matty K

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Comments

Boris Strandjev · Accepted Answer · 2012-04-20 12:52:11Z

0

You can use:

JSONArray jsonArray = jObject.getJSONArray("trips");

However consider using GSON for parsing json. It is lovely:

public class Class1 {
    private String erroCode;
    private String Processed;
    private Class2[] trips;
}

class Class2 {
    private String tripDestination;
    private String tripStartTime;
}

Gson gson = new Gson();
Class1 object = gson.fromJson(s, Class1.class);

edited Apr 20, 2012 at 12:52

answered Apr 20, 2012 at 12:45

Boris Strandjev

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3 Comments

Boris Strandjev Over a year ago

Sorry I am not familiar with this term.

Matty K Over a year ago

I was wondering if it used reflection to assign the members' values, since in your example they're declared private and there is no constructor and no setters.

Boris Strandjev Over a year ago

@MattyK It does use reflection. Some people requested properties would be supported as well. You can read more about that in SO here: stackoverflow.com/questions/6203487/…

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