JSONObject - How to get a value?
This may be helpful while searching keys present in nested objects and nested arrays. And this is a generic solution to all cases.
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class MyClass
{
public static Object finalresult = null;
public static void main(String args[]) throws JSONException
{
System.out.println(myfunction(myjsonstring,key));
}
public static Object myfunction(JSONObject x,String y) throws JSONException
{
JSONArray keys = x.names();
for(int i=0;i<keys.length();i++)
{
if(finalresult!=null)
{
return finalresult; //To kill the recursion
}
String current_key = keys.get(i).toString();
if(current_key.equals(y))
{
finalresult=x.get(current_key);
return finalresult;
}
if(x.get(current_key).getClass().getName().equals("org.json.JSONObject"))
{
myfunction((JSONObject) x.get(current_key),y);
}
else if(x.get(current_key).getClass().getName().equals("org.json.JSONArray"))
{
for(int j=0;j<((JSONArray) x.get(current_key)).length();j++)
{
if(((JSONArray) x.get(current_key)).get(j).getClass().getName().equals("org.json.JSONObject"))
{
myfunction((JSONObject)((JSONArray) x.get(current_key)).get(j),y);
}
}
}
}
return null;
}
}
Possibilities:
- "key":"value"
- "key":{Object}
- "key":[Array]
Logic :
- I check whether the current key and search key are the same, if so I return the value of that key.
- If it is an object, I send the value recursively to the same function.
- If it is an array, I check whether it contains an object, if so I recursively pass the value to the same function.
If it's a deeper key/value you're after and you're not dealing with arrays of keys/values at each level, you could recursively search the tree:
public static String recurseKeys(JSONObject jObj, String findKey) throws JSONException {
String finalValue = "";
if (jObj == null) {
return "";
}
Iterator<String> keyItr = jObj.keys();
Map<String, String> map = new HashMap<>();
while(keyItr.hasNext()) {
String key = keyItr.next();
map.put(key, jObj.getString(key));
}
for (Map.Entry<String, String> e : (map).entrySet()) {
String key = e.getKey();
if (key.equalsIgnoreCase(findKey)) {
return jObj.getString(key);
}
// read value
Object value = jObj.get(key);
if (value instanceof JSONObject) {
finalValue = recurseKeys((JSONObject)value, findKey);
}
}
// key is not found
return finalValue;
}
Usage:
JSONObject jObj = new JSONObject(jsonString);
String extract = recurseKeys(jObj, "extract");
Using Map code from https://stackoverflow.com/a/4149555/2301224
String loudScreaming = json.getJSONObject("LabelData").getString("slogan");