Concat two json objects in java

Question

I want to concat multiple json object.

I have two json like this

{"message":"test","status":"0"}

and this

{"message":"test-2","status":"1"}

result must be

[{"message":"test","status":"0"},{"message":"test-2","status":"1"}]

How can I do this in Java ?

You want to concat the values from JSON objects, or you want to create array of them ? You can refer to another link on SO: http://stackoverflow.com/questions/2403132/concat-multiple-jsonobjects — Mandar Pandit, Aug 07 '14 at 10:56
I can't use concat with json object.I want to create array of them — Tolgay Toklar, Aug 07 '14 at 10:57
Do you want to handle them as `String`s or as `JSONObject`s in a `JSONArray`? — , Aug 07 '14 at 10:58

score 5 · Answer 1 · answered Aug 07 '14 at 11:27

5

You can easily use JSONObject.toString() and concatenate the strings easily e.g

String x = "[" + obj1.toString() "," + obj2.toString() + "]";

or

StringBuilder newStr = new StringBuilder() ;
newStr.append("[").append(obj1.toString()).append(",").append(obj2.toString());

answered Aug 07 '14 at 11:27

Thusitha Thilina Dayaratne

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missed a + between obj1.toString() and "," – Jiwa Chhetri Oct 26 '21 at 18:17

shlomi33 · Accepted Answer · 2014-08-07T11:23:37.350

3

Do something like this:

List<String> array = new ArrayList<String>();
array.add("{\"message\":\"test\",\"status\":\"0\"}");
array.add("{\"message\":\"test-2\",\"status\":\"1\"}");
array.toString();

If you want to user support for JSON object in Java, consider using Gson:

import com.google.gson.JsonArray;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

public class Main {

    public static void main(String[] args) {
        JsonObject json1 = (JsonObject) new JsonParser().parse("{\"message\":\"test\",\"status\":\"0\"}");
        JsonObject json2 = (JsonObject) new JsonParser().parse("{\"message\":\"test-2\",\"status\":\"1\"}");
        JsonArray array = new JsonArray();
        array.add(json1);
        array.add(json2);
        System.out.println(array.toString());
    }
}

This would give you what you want this time using objects.

edited Aug 07 '14 at 11:23

answered Aug 07 '14 at 10:57

shlomi33

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'<>' operator is not allowed for source level below 1.7 for line 1 – Tolgay Toklar Aug 07 '14 at 11:00
3

And generics is not allowed before 1.5! So what?! – shlomi33 Aug 07 '14 at 11:01
Just do: new ArrayList() – shlomi33 Aug 07 '14 at 11:02
It's fixed but I have one more problem,I have to use this add method with jsonobject.But add method is only accepting string value.What can I do ? – Tolgay Toklar Aug 07 '14 at 11:06
@TolgayToklar What JSONObject are you using? – shlomi33 Aug 07 '14 at 11:07
I am using socket.io for java and socket event returning jsonobject for json data. – Tolgay Toklar Aug 07 '14 at 11:08
I am getting this error The method parse(String) in the type JsonParser is not applicable for the arguments (JSONObject) for jsonparser method – Tolgay Toklar Aug 07 '14 at 11:21
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/58871/discussion-between-shlomi33-and-tolgay-toklar). – shlomi33 Aug 07 '14 at 11:23

score 0 · Answer 3 · edited Aug 31 '16 at 05:24

private static void concatJSON() throws IOException, InterruptedException {

JSONParser parser = new JSONParser();
Object obj = parser.parse(new FileReader(new File(Main.class.getResource("/file/user.json").toURI())));

JSONObject jsonObj = (JSONObject) obj; //usernameJsonObj

String [] values = {"0.9" , Date.from(Calendar.getInstance().toInstant()).toLocaleString()},
        innermost = {"Accomplished", "LatestDate"}, 
        inner = {"Lesson1", "Lesson2", "Lesson3", "Lesson4"};
String in = "Jayvee Villa";

JSONObject jo1 = new JSONObject();
for (int i = 0; i < innermost.length; i++)
    jo1.put(innermost[i], values[i]);

JSONObject jo2 = new JSONObject();
for (int i = 0; i < inner.length; i++)
    jo2.put(inner[i], jo1);

JSONObject jo3 = new JSONObject();
jo3.put(in, jo2);

String merger = jsonObj.toString().substring(0, jsonObj.toString().length()-1) + "," +jo3.toString().substring(1);

System.out.println(merger);
FileWriter pr = new FileWriter(file);
pr.write(merger);
pr.flush();
pr.close();
}

Concat two json objects in java

3 Answers3

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