How to access nested elements of json object using getJSONArray method

Question

I have a JSON response that looks like this:

{
  "result": {
    "map": {
      "entry": [
        {
          "key": { "@xsi.type": "xs:string", "$": "ContentA" },
          "value": "fsdf"
        },
        {
          "key": { "@xsi.type": "xs:string", "$": "ContentB" },
          "value": "dfdf"
        }
      ]
    }
  }
}

I want to access the value of the "entry" array object. I am trying to access:

RESPONSE_JSON_OBJECT.getJSONArray("entry");

I am getting JSONException. Can someone please help me get the JSON array from the above JSON response?

Answer 1

You have to decompose the full object to reach the entry array.

Assuming REPONSE_JSON_OBJECT is already a parsed JSONObject.

REPONSE_JSON_OBJECT.getJSONObject("result")
    .getJSONObject("map")
    .getJSONArray("entry");

Answer 2

Try this code using Gson library and get the things done.

Gson gson = new GsonBuilder().create();

JsonObject job = gson.fromJson(JsonString, JsonObject.class);
JsonElement entry=job.getAsJsonObject("results").getAsJsonObject("map").getAsJsonArray("entry");

String str = entry.toString();

System.out.println(str);

Answer 3

I suggest you to use Gson library. It allows to parse JSON string into object data model. Please, see my example:

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.annotations.SerializedName;

public class GsonProgram {

    public static void main(String... args) {
        String response = "{\"result\":{\"map\":{\"entry\":[{\"key\":{\"@xsi.type\":\"xs:string\",\"$\":\"ContentA\"},\"value\":\"fsdf\"},{\"key\":{\"@xsi.type\":\"xs:string\",\"$\":\"ContentB\"},\"value\":\"dfdf\"}]}}}";

        Gson gson = new GsonBuilder().serializeNulls().create();
        Response res = gson.fromJson(response, Response.class);

        System.out.println("Entries: " + res.getResult().getMap().getEntry());
    }
}

class Response {

    private Result result;

    public Result getResult() {
        return result;
    }

    public void setResult(Result result) {
        this.result = result;
    }

    @Override
    public String toString() {
        return result.toString();
    }
}

class Result {

    private MapNode map;

    public MapNode getMap() {
        return map;
    }

    public void setMap(MapNode map) {
        this.map = map;
    }

    @Override
    public String toString() {
        return map.toString();
    }
}

class MapNode {

    List<Entry> entry = new ArrayList<Entry>();

    public List<Entry> getEntry() {
        return entry;
    }

    public void setEntry(List<Entry> entry) {
        this.entry = entry;
    }

    @Override
    public String toString() {
        return Arrays.toString(entry.toArray());
    }
}

class Entry {

    private Key key;
    private String value;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public Key getKey() {
        return key;
    }

    public void setKey(Key key) {
        this.key = key;
    }

    @Override
    public String toString() {
        return "[key=" + key + ", value=" + value + "]";
    }
}

class Key {

    @SerializedName("$")
    private String value;

    @SerializedName("@xsi.type")
    private String type;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    @Override
    public String toString() {
        return "[value=" + value + ", type=" + type + "]";
    }
}

Program output:

Entries: [[key=[value=ContentA, type=xs:string], value=fsdf], [key=[value=ContentB, type=xs:string], value=dfdf]]

If you not familiar with this library, then you can find a lot of informations in "Gson User Guide".