Example of JSON Object in Java
February 01, 2013
JSONObject is used to send and retreive data from server to client. JSON data has a format {"key":"value"}.
From server data will be sent to UI in the JSON format. While creating JSONObject, we need to put key and value.
There can be a JSON Array. The JSONArray data will look like {"res":[{"k20":"v20","k10":"v10"},{"k11":"v11","k21":"v21"},{"k22":"v22","k12":"v12"}]}.
There must be a JSON contract between client and server.
JSONTest.java
package com.concretepage; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; public class JSONTest { public static void main(String... args) throws JSONException{ final JSONObject res = new JSONObject(); //adding value in JSON object JSONArray jarray= new JSONArray(); for(int i=0;i<3;i++){ JSONObject ob = new JSONObject(); ob.put("k1"+i, "v1"+i); ob.put("k2"+i, "v2"+i); jarray.put(ob); } res.put("res", jarray); System.out.println("structure of created json object:"+res); //retrieving value from JSON object element wise System.out.println("retrieving value from JSON object element wise"); JSONArray output= res.getJSONArray("res"); for(int i=0;i<output.length();i++){ JSONObject ob= output.getJSONObject(i); System.out.print(ob.get("k1"+i)); System.out.println(ob.get("k2"+i)); } } }
structure of created json object:{"res":[{"k20":"v20","k10":"v10"},{"k11":"v11","k21":"v21"},{"k22":"v22","k12":"v12"}]} retrieving value from JSON object element wise v10v20 v11v21 v12v22