[java] How to access nested elements of json object using getJSONArray method

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?

This question is related to java json arrays

The answer is


I'm also faced with this issue. So I solved with recursion. Maybe it will be helpfull. I created method.I used org.json library.

    public static JSONObject function(JSONObject obj, String keyMain, String newValue) throws Exception {
    // We need to know keys of Jsonobject
    Iterator iterator = obj.keys();
    String key = null;
    while (iterator.hasNext()) {
        key = (String) iterator.next();
        // if object is just string we change value in key
        if ((obj.optJSONArray(key)==null) && (obj.optJSONObject(key)==null)) {
            if ((key.equals(keyMain)) && (obj.get(key).toString().equals(valueMain))) {
                // put new value
                obj.put(key, newValue);
                return obj;
            }
        }

        // if it's jsonobject
        if (obj.optJSONObject(key) != null) {
            function(obj.getJSONObject(key), keyMain, valueMain, newValue);
        }

        // if it's jsonarray
        if (obj.optJSONArray(key) != null) {
            JSONArray jArray = obj.getJSONArray(key);
            for (int i=0;i<jArray.length();i++) {
                    function(jArray.getJSONObject(i), keyMain, valueMain, newValue);
            }
        }
    }
    return obj;
}

if you have questions, I can explain...


This is for Nikola.

    public static JSONObject setProperty(JSONObject js1, String keys, String valueNew) throws JSONException {
    String[] keyMain = keys.split("\\.");
    for (String keym : keyMain) {
        Iterator iterator = js1.keys();
        String key = null;
        while (iterator.hasNext()) {
            key = (String) iterator.next();
            if ((js1.optJSONArray(key) == null) && (js1.optJSONObject(key) == null)) {
                if ((key.equals(keym)) && (js1.get(key).toString().equals(valueMain))) {
                    js1.put(key, valueNew);
                    return js1;
                }
            }
            if (js1.optJSONObject(key) != null) {
                if ((key.equals(keym))) {
                    js1 = js1.getJSONObject(key);
                    break;
                }
            }
            if (js1.optJSONArray(key) != null) {
                JSONArray jArray = js1.getJSONArray(key);
                JSONObject j;
                for (int i = 0; i < jArray.length(); i++) {
                    js1 = jArray.getJSONObject(i);
                    break;
                }
            }
        }
    }
    return js1;
}


public static void main(String[] args) throws IOException, JSONException {
    String text = "{ "key1":{ "key2":{ "key3":{ "key4":[ { "fieldValue":"Empty", "fieldName":"Enter Field Name 1" }, { "fieldValue":"Empty", "fieldName":"Enter Field Name 2" } ] } } } }";
    JSONObject json = new JSONObject(text);
    setProperty(json, "ke1.key2.key3.key4.fieldValue", "nikola");
    System.out.println(json.toString(4));

}

If it's help bro,Do not forget to up for my reputation)))


You can try this:

JSONObject result = new JSONObject("Your string here").getJSONObject("result");
JSONObject map = result.getJSONObject("map");
JSONArray entries= map.getJSONArray("entry");

I hope this helps.


I would also try it this way

1) Create the Java Beans from the JSON schema

2) Use JSON parser libraries to avoid any sort of exception

3) Cast the parse result to the Java object that was created from the initial JSON schema.

Below is an example JSON Schema"

{
  "USD" : {"15m" : 478.68, "last" : 478.68, "buy" : 478.55, "sell" : 478.68,  "symbol" : "$"},
  "JPY" : {"15m" : 51033.99, "last" : 51033.99, "buy" : 51020.13, "sell" : 51033.99,  "symbol" : "¥"},
}

Code

public class Container { 

    private JPY JPY;

    private USD USD;

    public JPY getJPY ()
    {
        return JPY;
    }

    public void setJPY (JPY JPY)
    {
        this.JPY = JPY;
    }

    public USD getUSD ()
    {
        return USD;
    }

    public void setUSD (USD USD)
    {
        this.USD = USD;
    }

    @Override
    public String toString()
    {
        return "ClassPojo [JPY = "+JPY+", USD = "+USD+"]";
    }
}


public class JPY
{    
    @SerializedName("15m")
    private double  fifitenM;

    private String symbol;

    private double last;

    private double sell;

    private double buy;

    public double getFifitenM ()
    {
        return fifitenM;
    }

    public void setFifitenM (double fifitenM)
    {
        this.fifitenM = fifitenM;
    }

    public String getSymbol ()
    {
        return symbol;
    }

    public void setSymbol (String symbol)
    {
        this.symbol = symbol;
    }

    public double getLast ()
    {
        return last;
    }

    public void setLast (double last)
    {
        this.last = last;
    }

    public double getSell ()
    {
        return sell;
    }

    public void setSell (double sell)
    {
        this.sell = sell;
    }

    public double getBuy ()
    {
        return buy;
    }

    public void setBuy (double buy)
    {
        this.buy = buy;
    }

    @Override
    public String toString()
    {
        return "ClassPojo [15m = "+fifitenM+", symbol = "+symbol+", last = "+last+", sell = "+sell+", buy = "+buy+"]";
    }
}


public class USD
{
    @SerializedName("15m")
    private double fifitenM;

    private String symbol;

    private double last;

    private double sell;

    private double buy;

    public double getFifitenM ()
    {
        return fifitenM;
    }

    public void setFifitenM (double fifitenM)
    {
        this.fifitenM = fifitenM;
    }

    public String getSymbol ()
    {
        return symbol;
    }

    public void setSymbol (String symbol)
    {
        this.symbol = symbol;
    }

    public double getLast ()
    {
        return last;
    }

    public void setLast (double last)
    {
        this.last = last;
    }

    public double getSell ()
    {
        return sell;
    }

    public void setSell (double sell)
    {
        this.sell = sell;
    }

    public double getBuy ()
    {
        return buy;
    }

    public void setBuy (double buy)
    {
        this.buy = buy;
    }

    @Override
    public String toString()
    {
        return "ClassPojo [15m = "+fifitenM+", symbol = "+symbol+", last = "+last+", sell = "+sell+", buy = "+buy+"]";
    }
}


public class MainMethd
{
    public static void main(String[] args) throws JsonIOException, JsonSyntaxException, FileNotFoundException {
        // TODO Auto-generated method stub
        JsonParser parser = new JsonParser();
        Object obj = parser.parse(new FileReader("C:\\Users\\Documents\\file.json"));
        String res = obj.toString();
        Gson gson = new Gson();
        Container container = new Container();
        container = gson.fromJson(res, Container.class);
        System.out.println(container.getUSD());
        System.out.println("Sell Price : " + container.getUSD().getSymbol()+""+ container.getUSD().getSell());
        System.out.println("Buy Price : " + container.getUSD().getSymbol()+""+ container.getUSD().getBuy());
    }

}

Output from the main method is:

ClassPojo [15m = 478.68, symbol = $, last = 478.68, sell = 478.68, buy = 478.55]

Sell Price : $478.68

Buy Price : $478.55

Hope this helps.


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);

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".


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