How to create JSON Object using String?

Question

I want to create a JSON Object using String.

Example : JSON {"test1":"value1","test2":{"id":0,"name":"testName"}}

In order to create the above JSON I am using this.

String message;
JSONObject json = new JSONObject();

json.put("test1", "value1");

JSONObject jsonObj = new JSONObject();

jsonObj.put("id", 0);
jsonObj.put("name", "testName");
json.put("test2", jsonObj);

message = json.toString();
System.out.println(message);

I want to know how can I create a JSON which has JSON Array in it.

Below is the sample JSON.

{
  "name": "student",
   "stu": {
    "id": 0,
    "batch": "batch@"
  },
  "course": [
    {
      "information": "test",
      "id": "3",
      "name": "course1"
    }
  ],
  "studentAddress": [
    {
      "additionalinfo": "test info",
      "Address": [
        {
          "H.No": "1243",
          "Name": "Temp Address",
          "locality": "Temp locality",
           "id":33          
        },
        {
           "H.No": "1243",
          "Name": "Temp Address",
          "locality": "Temp locality", 
           "id":33                   
        },        
        {
           "H.No": "1243",
          "Name": "Temp Address",
          "locality": "Temp locality", 
           "id":36                   
        }
      ],
"verified": true,
    }
  ]
}

Thanks.

score 229 · Accepted Answer · edited Feb 03 '21 at 01:29

229

JSONArray may be what you want.

String message;
JSONObject json = new JSONObject();
json.put("name", "student");

JSONArray array = new JSONArray();
JSONObject item = new JSONObject();
item.put("information", "test");
item.put("id", 3);
item.put("name", "course1");
array.put(item);

json.put("course", array);

message = json.toString();

// message
// {"course":[{"id":3,"information":"test","name":"course1"}],"name":"student"}

edited Feb 03 '21 at 01:29

Cherlan-Miche PHILIPPE

24
1
9

answered Nov 21 '13 at 09:37

srain

8,506
6
28
42

How do I convert it back to a `JSONObject` from a string? – morha13 Feb 23 '18 at 17:42
`JSONObject jsonObj = new JSONObject("your_json_string");` – Camille Feb 28 '18 at 07:44
FYI that this will fail to parse JSON arrays (even though they are technically valid JSON). For example, trying `JSONObject("[{\"foo\":2, \"bar\": 3}]");` results in `A JSONObject text must begin with '{' at 1 [character 2 line 1]` – user2490003 Aug 21 '18 at 05:44

score 13 · Answer 2 · edited Aug 22 '18 at 07:55

13

In contrast to what the accepted answer proposes, the documentation says that for JSONArray() you must use put(value) no add(value).

https://developer.android.com/reference/org/json/JSONArray.html#put(java.lang.Object)

(Android API 19-27. Kotlin 1.2.50)

edited Aug 22 '18 at 07:55

BDL

19,702
16
49
50

answered Aug 22 '18 at 06:51

Walter Palacios

418
4
8

score 4 · Answer 3 · answered Aug 24 '20 at 09:48

4

If you use the gson.JsonObject you can have something like that:

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

String jsonString = "{'test1':'value1','test2':{'id':0,'name':'testName'}}"
JsonObject jsonObject = (JsonObject) jsonParser.parse(jsonString)

answered Aug 24 '20 at 09:48

Lei00

41
1

It worked for me, the simplest solution, thanks – Billyjoker Nov 29 '20 at 16:59

Valentyn Kolesnikov · Answer 4 · 2021-03-06T08:17:02.100

Underscore-java can create json from an object.

    String message = U.objectBuilder()
            .add("course", U.arrayBuilder()
                    .add(U.objectBuilder()
                            .add("id", 3)
                            .add("information", "test")
                            .add("name", "course1")
                    ))
            .add("name", "student")
            .toJson();
    System.out.println(message);

// {
//   "course": [
//     {
//       "id": 3,
//       "information": "test",
//       "name": "course1"
//     }
//   ],
//   "name": "student"
// }

score 0 · Answer 5 · answered Mar 10 '22 at 17:20

0

 String jsonString = "{'element1':'value1','element2':{'id':0,'name':'testName'}}";
        JsonObject jsonObject = (JsonObject) JsonParser.parseString(jsonString);

answered Mar 10 '22 at 17:20

Carlos Noé

49
1
7

How to create JSON Object using String?

5 Answers5

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