Java – Get list of id's from JSON with a variable depth

I have a JSON file with a fluctuating depth and each node (different depth). So it’s built like a General tree :

And here is a sample json (not the real one but a mock file but the structure remains the same) :

{
  "arbre" : {
    "children" : [
      {
        "id" : 1,
        "children" : [
          {
            "id" : 3,
            "children" : [
              {
                "id" : 6,
                "children" : []
              }
            ]
          },
          {
            "id" : 4,
            "children": []
          },
          {
            "id" : 5,
            "children": []
          }
        ]
      },
      {
        "id" : 2,
        "children" : [
          {
            "id" : 7,
            "children" : 
            [
              {
                "id" : 8,
                "children" : [
                  {
                    "id" : 9,
                    "children" : []
                  }
                ]
              },
              {
                "id" : 10,
                "children" : [
                  {
                    "id" : 11,
                    "children" : []
                  }
                ]
              }
            ]
          }
        ]
      }
    ]
  }
}

I’m trying to build multiple list of id for each subtrees, so for exemple I need :

• 1, 3, 6
• 1, 4
• 1, 5
• 2, 7, 8, 9
• 2, 7, 10, 11

I previously developped a routine that traverse the entire tree (recursive) using jackson and don’t know if I can adapt it to this use case.

Here it is :

/**
     * getJSONNode: not return value, recursive function that will browse (uses functionalities and objects of the com.fasterxml.jackson library)
     * 
     * 
     * {talendTypes} String, JsonNode
     * 
     * {Category} User Defined
     * 
     * {param} JsonNode(jNode) input: the function will check if the node is an array of object and will process and keep iterate until it reaches the bottom of the tree
     * {param} string(filepath) input: The string is a path to a directory where the temp files will be stored
     * 
     * {example} getJSONNode(jNode, "/test/") # Files will be generated in the directory /test/
     */
    public static void getJSONNode(JsonNode jNode, String filepath) throws IOException {
        //System.out.println("Get Node");
        JsonNode tempNoded = jNode.get("children");
        if(tempNoded.isArray()) {
            for(int i = 0; i < tempNoded.size(); i++) {
                System.out.println("Name : " + tempNoded.get(i).get("name"));
                System.out.println("Title : " + tempNoded.get(i).get("title"));
                System.out.println("Title : " + tempNoded.get(i).get("id"));
                System.out.println("================== Writing file ===================");
                String id = tempNoded.get(i).get("id").toString();
                String name = tempNoded.get(i).get("name").toString();
                String title = tempNoded.get(i).get("title").toString();
                String color = tempNoded.get(i).get("color").toString();
                String order = tempNoded.get(i).get("order").toString();
                String parentId = tempNoded.get(i).get("parentId").toString();
                String persons = tempNoded.get(i).get("persons").toString();
                String profils = tempNoded.get(i).get("profils").toString();
                String paramNoeud = tempNoded.get(i).get("paramNoeud").toString();
                String description = tempNoded.get(i).get("description").toString();
                // disable not present in all dimensions so not usable
                //String disabled = tempNoded.get(i).get("disabled").toString();
                String oldId = tempNoded.get(i).get("oldId").toString();
                
                String str = id + ";" + name + ";" + title + ";" + color + ";" + order + ";" + parentId + ";" + persons + ";" + profils + ";" + paramNoeud + ";" + description + ";" + oldId;
                byte[] strToBytes = str.getBytes();
                
                String filename = (name + "_" + order + ".csv").replaceAll(""", "");
                
                File file = new File(filepath + filename);
                file.getParentFile().mkdirs();
                file.createNewFile();               
                FileOutputStream outputStream = new FileOutputStream(filepath + filename);
                
                outputStream.write(strToBytes);
                outputStream.close();
                
                getJSONNode(tempNoded.get(i), filepath);
            }
            
        }
    }

So is there a method to build those lists and modify my routine to do it or something else (another routine, …)

Thanks