Develop Reference

How to access JSON value?

Very new to JSON, this is probably very simple but I'm not sure how to access the "coordinates" in this JSON I know how to go from resourceSets to resources but get stuck at "point":
{
"resourceSets":[
{
"estimatedTotal":1,
"resources":[
{
"__type":"Location:http:\/\/schemas.microsoft.com\/search\/local\/ws\/rest\/v1",
"bbox":[
51.3223903,
-0.2634519,
51.3246386,
-0.2598541
],
"name":"name",
"point":{
"type":"Point",
"coordinates":[
51.3235145,
-0.261653
]
}
}
]
}
]
}
My code so far:
JSONParser parser = new JSONParser();
JSONObject jObj = (JSONObject)parser.parse(result);
JSONArray jsonArray = (JSONArray)jObj.get("resourceSets");
for (int i = 0; i < jsonArray.size(); i ++) {
JSONObject jObjResourceSets = (JSONObject)jsonArray.get(i);
JSONArray jsonArray2 = (JSONArray)jObjResourceSets.get("resources");
System.out.println("Coords" + jObjResourceSets.get("point"));
}

Lets analyse what you're doing (and need to be doing), step by step, in order to get the "coordinates".
First of all, JSON is a great language to transfer static data. It works like a dictionary, where you have a key and the respective value. The key should always be a String, but the value can be a String, an int/double or even an array of other JSON objects. That's what you have.
For instance, "estimatedTotal" is an element (JSONObject) from the "resourceSet" array (JSONArray).
JSONArray jsonArray = (JSONArray)jObj.get("resourceSets");
What you're saying here is straight forward: from your overall JSONObject - jObj - you want to extract the array with key "resourceSets".
Now you have direct access to "resourceSets" array elements: "estimatedTotal", "resources", etc. So, by applying the same logic, in order to access "coordinates" we need to access the "resources" array. And by that I mean to create a JSONArray object like we did before.
JSONArray jsonResourcesArray = (JSONArray)jObjResourceSets.get("resources");
I hope it's clear what's the content of jsonResourcesArray here. It's the JSON array of "__type", "bbox", "name", "point", (...). The Coordinates howevere are inside "point" JSON object. How do we access it?
JSONObject jsonPointObject = (JSONObject) jsonResourcesArray.get("point");
And you know by know that "jsonPointObject" has as its values the following JSON objects: "type" and "coordinates". Coordinates is an array of values, so do we have to use JSONArray or JSONObject?
JSONArray jsonCoordinatesArray = (JSONArray) jsonPointObject.get("coordinates");
From which we mean: from the jsonPointObject we want to extract the array that has key "coordinates". Now your array is a JSONArray with values of jsonCoordinatesArray.get(0) and jsonCoordinatesArray.get(0).
Now you have, not only the code to get those values, but the understanding of how JSON works and how Java interacts with it so you can solve any Json problem from now on.

Normally this code works for the given JSON object. However I'll put the tested formatted JSON value below the java code so you can test it as well.
Note that this code will get you all the coordinates of all the elements in your object.
public static void main(String[] args) throws Exception {
String result = getJsonString();
// Getting root object
JSONParser parser = new JSONParser();
JSONObject jObj = (JSONObject)parser.parse(result);
// Getting resourceSets Array
JSONArray jsonArray = (JSONArray)jObj.get("resourceSets");
for (int i = 0; i < jsonArray.size(); i++) {
// Getting the i object of resourceSet
JSONObject jObjResourceSets = (JSONObject) jsonArray.get(i);
// Getting resources list of the current element
JSONArray jsonArray2 = (JSONArray) jObjResourceSets.get("resources");
for (int j = 0; j < jsonArray2.size(); j++) {
// Getting the j resource of the resources array
JSONObject resource = (JSONObject) jsonArray2.get(j);
// Getting the point object of the current resource
JSONObject point = (JSONObject) resource.get("point");
// Getting the coordinates list of the point
JSONArray coordinates = (JSONArray) point.get("coordinates");
for (int k = 0; k < coordinates.size(); k++) {
System.out.println("Coordinates[" + k + "]: " + coordinates.get(k));
}
// Printing an empty line between each object's coordinates
System.out.println();
}
}
}
The tested JSON Object:
{
"resourceSets":[
{
"estimatedTotal":1,
"resources":[
{
"__type":"Location:http:\/\/schemas.microsoft.com\/search\/local\/ws\/rest\/v1",
"bbox":[
51.3223903,
-0.2634519,
51.3246386,
-0.2598541
],
"name":"name",
"point":{
"type":"Point",
"coordinates":[
51.3235145,
-0.261653
]
}
}
]
}
]
}
If it worked please mark it as the answer.
Good luck ^^
B.

You need the following piece of code to get the data.
JSONArray jsonArray2 = (JSONArray)jObjResourceSets.get("resources");
/**
* here we should note that the "resources" is only having one JSON object hence we can take it as below
* from 0th index using ((JSONObject)jsonArray2.get(0)) these piece of code and the next part is to take the point JSONObject
* from the object.
*/
JSONObject temp = (JSONObject)((JSONObject)jsonArray2.get(0)).get("point");
System.out.println("Coords"+temp.get("coordinates")); //this will give you the coordinates array
//now if you want to do further processing, traverse in the jsonArray like below
JSONArray arr= (JSONArray)temp.get("coordinates");
System.out.println("X coordinate:"+arr.get(0));
System.out.println("Y coordinate:"+arr.get(1));
For more information and further details on JSONObject and JSONArray you can go through this linkparsing-jsonarray-and-jsonobject-in-java-using-json-simple-jar
json-simple-example-read-and-write-json

count key value in JSON and extract values

I have following JSONObject (not array, which I don't mind to convert). I am trying to do two things:
get the count of genre entry as "poetry" (count = 2).
get the key value of author name and genre:
authorName = malcolm
genreName = newsarticle
authorName = keats
genreName = poetry
{ "AddressBook" :{
"Details" :{
"authorname" :{
"Author-malcolm":{
"genre" :"poetry"
}
"Author-keats":{
"genre" :"poetry"
}
}
}
}
}
Code which I tried:
public static void main(String[] args) throws Exception, IOException, ParseException {
JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader("My path to JSON"));
JSONObject jsonObject = (JSONObject) obj;
JSONArray arrayhere = new JSONArray();
arrayhere.add(obj);
System.out.println(arrayhere);
int count = 0;
for(int i = 0; i < arrayhere.size(); i++) {
JSONObject element = arrayhere.getJSONObject(i);//The method getJSONObject(int) is undefined for the type JSONArray
String branchName = element.getString("genre");//The method getString(String) is undefined for the type JSONObject
if(branchName.equals("poetry")) {
count ++;
}
}
System.out.println("Count f0r poetry genre=" + count);
}
}
I have looked at solutions all over. There is no question similar to this at stackoverflow. I am not sure if the procedure is correct.

A few problems here.
First, I'm not sure where you got that example JSON but you can't work with that. That's not even valid JSON Formatting.
Looks like you want something like this:
{
AddressBook:
[
{
authorname: "author-malcom",
genre:"poetry"
},
{
authorname: "author-keats",
genre: "poetry"
}
]
}
That's the structure you're trying to create in JSON.
So, you're parsing this in from a file into a JSONObject that has a key called AddressBook inside of it. That key points to an array of JSONObjects representing authors. Each of those objects will have a key called genre. You're trying to access the genre key and count on a condition.
What you did above was create attempt to create a JSONObject from an invalid string, and then add the entire JSONObject itself into the JSONArray. JSONArray.add() doesn't convert an object to an array, it literally adds it onto the array.
jsonObj => {"Name":"name1","Id":1000}
jsonArray.add(jsonObj)
jsonArray => [{"Name":"name1","Id":1000}]
That's what you did in your code above. You didn't create an array from a JSONObject, you added an object to the array.
Proper use is going to look like:
Object obj = parser.parse(new FileReader("path_to_file"));
JSONObject jobj = (JSONObject) obj;
//access key AddressBook
JSONArray author_array = jobj.getJSONArray("AddressBook");
int poetry = 0;
for(int i = 0; i < author_array.length(); i++) {
JSONObject author = (JSONObject) author_array.get(i);
if(author.getString("genre").equals("poetry")) {
poetry++;
}
}
To summarize, you're problems come from a lack of understanding about JSON Formatting and how to access elements within a JSON Object.
Paste in the sample JSONObject I gave you above here. That site will let you visualize what you're working with.

Android: accessing levels in JSON response

I am trying to get all the data coming from a API service, but I am having problems accessing the different "levels" inside the JSON response.
I believe my main problem comes when the inner levels include []
I am showing here a reduced part of the JSON response (the entire response is huge). But this part represent clearly my issue
{
   “CustomerList”:{
      “CustomerType”:”residential”,
      “maxAllowed”:”256”,
      "serverdate":"2017-05-02",
      “Purchases”:[
         {
            “Car”:[
               {
                  “customerName”:”Fredrik”,
                  “price”:”25890”,
                  “currency”:”EUR”,
                  “Item”:{
                     “code”:”Audi”,
                     “model”:”A3”,
                     “engine”:”diesel”,
                     “data”:”2017-03-12”,
                     "$":"\n"
                  },
                  "Destination":{
                     “country”:”Germany”,
                     “arrivalDate”:”March 25”,
                     "id":"02201403",
I have been able to access CustomerList and Purchases like this
JSONObject customer = (JSONObject) response.get("CustomerList");
JSONArray purchases = customer.getJSONArray("Purchases");
However now I am getting troubles accessing inner fields like Car, Item or Destination and their elements.
The following gives me JSONException
for (int i = 0;i< purchases.length();i++){
JSONObject car = purchases.getJSONObject(i);
String custName = car.getString("customerName");

In your case, you are getting the wrong object,
Purchases is an JSONArray who contains objects of a supposed class Purchase. And every instance of it has a instance of a JSONArray named Car (who contains Cars).
Given that, the way to access to the first car is :
for (int i = 0;i< purchases.length();i++){
JSONObject p = purchases.getJSONObject(i);
JSONObject car = p.getJSONObject(0);
String custName = car.getString("customerName");
I encourage you strongly to use a JSON serializer like gson to avoid treating with these issues. Take a look to jsonschema2pojo to generate the classes of your hierachy

Car is a JSONArray, and not a JSONObject
for (int i = 0;i< purchases.length();i++){
JSONArray array = purchases.getJSONArray(i);
for (int j = 0; j < array.length(); j++){
// loop through here again to get the JSONObject
}
}
In the inner loop, you get JSONObject and can call
String custName = array.getJSONObject(j).getString("customerName");
If you look at the exception you will probably see something likeyou cannot cast a ... to a JSONObject

Car is also JSONArray so try like below:
for (int i = 0;i< purchases.length();i++){
JSONArray carArr = purchases.getJSONArray(i);
for (int j = 0;j< carArr.length();j++){
JSONObject car = carArr.getJSONObject(j);
String custName = car.getString("customerName");
}
}

Get the count of entries from a json file

I am trying to get json data from a fake api call and need to get the count of the items in it(so that in future I can call the actual restful service). I am not able to get the number of departments in the json. I am expecting the result as 4(int) here.
I am not able to get the string value(json) for the code below:
String json = client.target("file:///C:/Program%20Files%20(x86)/apache-tomcat-8.0.35/webapps/GetProducts.json").request(MediaType.TEXT_PLAIN).get(String.class);
Please find below the entire code:
String json = client.target("file:///C:/Program%20Files%20(x86)/apache-tomcat-8.0.35/webapps/GetProducts.json").request(MediaType.TEXT_PLAIN).get(String.class);
JSONObject jsnobject = new JSONObject(json);
JSONArray jsonArray = jsnobject.getJSONArray("locations");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject explrObject = jsonArray.getJSONObject(i);
}
JSON Sample:
{
"Department":
[
{"SectionId":"1","SectionName":"Childrens Wear"},
{"SectionId":"2","SectionName":"Womens Wear"},
{"SectionId":"3","SectionName":"F&A"},
{"SectionId":"1","SectionName":"Mens Wear"}
]
}
I am new to java as well as api's.
Thanks,

You are either using incorrect key in code or you posted incorrect JSON example. You used locations as the key incode however there is no value against that key in sample JSON. You need to use Department as the key.
JSONArray jsonArray = jsnobject.getJSONArray("Department");

Android parse Json array of Strings

How can I parse in Android a Json array of strings and save it in a java string array ( like: xy[ ] ) ?
My Json to be parsed :
[
{
"streets": [ "street1", "street2", "street3",... ],
}
]
Later in my code I want to populated with that array a spinner item in my layout.
Everything i tried enden with only one street item listed in the spinner.

To parse
try {
JSONArray jr = new JSONArray("Your json string");
JSONObject jb = (JSONObject)jr.getJSONObject(0);
JSONArray st = jb.getJSONArray("streets");
for(int i=0;i<st.length();i++)
{
String street = st.getString(i);
Log.i("..........",""+street);
// loop and add it to array or arraylist
}
}catch(Exception e)
{
e.printStackTrace();
}
Once you parse and add it to array. Use the same to populate your spinner.
[ represents json array node
{ represents json object node

Try this..
JSONArray arr = new JSONArray(json string);
for(int i = 0; i < arr.length(); i++){
JSONObject c = arr.getJSONObject(i);
JSONArray ar_in = c.getJSONArray("streets");
for(int j = 0; j < ar_in.length(); j++){
Log.v("result--", ar_in.getString(j));
}
}

We need to make JSON object first. For example,
JSONObject jsonObject = new JSONObject(resp);
// resp is your JSON string
JSONArray arr = jsonObject.getJSONArray("results");
Log.i(LOG, "arr length = " + arr.length());
for(int i=0;i<arr.length();i++)
{...
arr may contains other JSON Objects or JSON array. How to convert the JSON depends on the String. There is a complete example with some explanation about JSON String to JSON array can be found at http://www.hemelix.com/JSONHandling