how to rearrange the json array based on id in java

Question

I want to rearrange the JSON, now i am getting like this:

[{"router_id":"1101","floor_id":"20","building_id":"2","router_name":"1101"}, {"router_id":"1102","floor_id":"20","building_id":"2","router_name":"1102"},{"router_id":"0","floor_id":"20","building_id":"2","router_name":"pancoordinator"}, {"router_id":"1104","floor_id":"20","building_id":"2","router_name":"1104"}]

But i need JSON like following one:

{"buildings": [{"building_id": "2","floors": [{"floor_id": "20","routers": [{"router_id":"1","router_name": "a"},{"router_id":"2","router_name": "b"}]}]}]}

This is my code:

    @Override
    public List<JSONObject> getFullRouterList() throws Exception {

    System.out.println("in dao of getFullRouterList ");
    session = sessionFactory.openSession();
    tx = session.beginTransaction();
    String sql = "SELECT building_id, floor_id, router_id, router_name FROM router_details";
    SQLQuery query = session.createSQLQuery(sql);

    List<Object[]> list = query.list();
    List<JSONObject> result = new ArrayList<>();

    for(Object[] rows: list) {
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("building_id", rows[0].toString());
        jsonObject.put("floor_id", rows[1].toString());
        jsonObject.put("router_id", rows[2].toString());
        jsonObject.put("router_name", rows[3].toString());
        result.add(jsonObject);
    }

    tx.commit();
    session.close();
    return result;  
}

Answer 1

https://github.com/octomix/josson

List<Object[]> list = query.list();
ObjectMapper mapper = new ObjectMapper();
ArrayNode array = mapper.createArrayNode();

for(Object[] rows: list) {
    ObjectNode object = mapper.createObjectNode();
    object.put("building_id", rows[0].toString());
    object.put("floor_id", rows[1].toString());
    object.put("router_id", rows[2].toString());
    object.put("router_name", rows[3].toString());
    array.add(object);
}

Josson josson = Josson.create(array);
JsonNode node = josson.getNode(
    "group(building_id).map(" +
    "    building_id," +
    "    floors: elements.group(floor_id).map(" +
    "        floor_id," +
    "        routers: elements.map(" +
    "            router_id, router_name)" +
    "    )" +
    ")" +
    ".toObject('buildings')");
System.out.println(node.toPrettyString());

Output

{
  "buildings" : [ {
    "building_id" : "2",
    "floors" : [ {
      "floor_id" : "20",
      "routers" : [ {
        "router_id" : "1101",
        "router_name" : "1101"
      }, {
        "router_id" : "1102",
        "router_name" : "1102"
      }, {
        "router_id" : "0",
        "router_name" : "pancoordinator"
      }, {
        "router_id" : "1104",
        "router_name" : "1104"
      } ]
    } ]
  } ]
}