Gson - Add to nested JsonObject without removing previously written data

Question

This is "test.json" before I run my code:

{
  "example1": {
    "example2": {
      "example3": 30
    }
  }
}

When I run this code:

public static void test() throws IOException {

    Path fileName = Paths.get("src/test.json");

    try (BufferedReader reader = Files.newBufferedReader(fileName);
        BufferedWriter writer = Files.newBufferedWriter(fileName, StandardOpenOption.WRITE)) {
        Gson gson = new GsonBuilder().setPrettyPrinting().create();
        JsonObject value = gson.fromJson(reader, JsonObject.class);

        JsonObject object1 = new JsonObject();
        JsonObject object2 = new JsonObject();

        value.add("example1", object1);
        object1.add("example2", object2);
        object2.addProperty("example4", 40);

        gson.toJson(value, writer);

    }
    
}

Then this happens to "test.json":

{
  "example1": {
    "example2": {
      "example4": 40
    }
  }
}

How can I add the data from "example4" to "example2" without removing "example3"?

Your JSON text is invalid as the first curly brace is backwards. Is this a typo? Have you checked the full JSON with an online JSON checker? — DontKnowMuchBut Getting Better, Aug 30 '20 at 17:19
Does this answer your question? [In Gson, how do I add a JsonArray to a JsonObject?](https://stackoverflow.com/questions/38642868/in-gson-how-do-i-add-a-jsonarray-to-a-jsonobject) — DontKnowMuchBut Getting Better, Aug 30 '20 at 17:27
It rather looks like they want to merge two JSON objects. Maybe `value.getAsJsonObject("example1").getAsJsonObject("example2").addProperty("example4", 40)` would already solve this. Though it also depends on the real (non-example) data they are using. — Marcono1234, Aug 30 '20 at 22:31

Gson - Add to nested JsonObject without removing previously written data

0 Answers0