CODEWITHSUNDEEP
javajson
codemanian_helloworld
codemanian_helloworld

Reputation: 19

How can I make an JSON in Java with org.json which does look like this example?

So, I tried something with java which looks like this, but the output does not look nice.

One of the code-examples I tried to make a json file with:

        String name = "usericals.json";
        JSONObject jsonObj = new JSONObject();

        JSONArray scene = new JSONArray();
        JSONArray element = new JSONArray();


        jsonObj.put("scene", scene);
        for (int i = 0; i < 1; i++) {
            for (int ii = 0; ii < 1; ii++) {
                element.put(write);
            }
            jsonObj.put("element", element);

        }
        scene.put(element);

        try (PrintWriter writer = new PrintWriter("new.json", "UTF-8")) {
            writer.write(jsonObj.toString(4));
        } catch (Exception ex) {
            System.out.println("exception " + ex);
        }

I wanted to make a json file which looks like this but I cannot get it right. I am creating with my code above only arrays. Does anyone have an idea or suggestion?

The JSON File I want:

{
  "scene": [
    {
      "id": 0,
      "calendar_event": "urlaub",
      "element": [
        {
          "anything": ""
        },
        {
          "anything": ""
        }
      ]
    },
    {
      "id": 1,
      "calendar_event": "urlauburlaub",
      "element": [
        {
          "anything": ""
        },
        {
          "anything": ""
        }
      ]
    },
    {
      "id": 2,
      "calendar_event": "urlauburlauburlaub",
      "element": [
        {
          "anything": ""
        },
        {
          "device": "",
          "anything": ""
        }
      ]
    },
    {
      "id": 3,
      "calendar_event": "urlauburlauburlauburlaub",
      "element": [
        {
          "anything": ""
        },
        {
          "anything": ""
        }
      ]
    }
  ]
}

Upvotes: 2

Views: 292

Answers (2)

user1039663
user1039663

Reputation: 1343

Use JSONObject recursively. Try something like this (I add some extra indentation so it can be readed easily, but on real projects better use functions instead):

JSONObject json = new JSONObject();
  JSONArray scene = new JSONArray();
    JSONObject node = new JSONObject();
    node.put("id", 0);
    node.put("calendar_event", "urlaub");
      JSONArray element = new JSONArray();
        JSONObject enode = new JSONObject();
        enode.put("anything", "");
      element.add(enode);
      //...
    node.put("element", element);
  scene.add(node);
json.put("scene", scene);
//...

Note like this you generate manually the JSONs, but there are other libraries that scan objects to generate jsons. Depending on your needs, it could be easer, but remember that making so you are going to overhead everything because you are going to need to hold in memory two copies of the same tree. Also dealing with hierarchical structures maybe a problem using plain java objects.

Upvotes: 0

stream28
stream28

Reputation: 141

I suggest using library for that. Jackson or GSON would be a good choice.

Instead of manually creating json field by field you could create POJOs and then use Jackson's ObjectMapper. Example:

public class Car {

    private String color;
    private String type;

    // standard getters setters
}

and then

ObjectMapper objectMapper = new ObjectMapper();
Car car = new Car("yellow", "renault");
objectMapper.writeValue(new File("target/car.json"), car);

Which will give

{"color":"yellow","type":"renault"}

Google has a lot of jackson tutorials!

Upvotes: 1

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