Multidimensional Array to JSON (and back) in Java

Question

I'm new to Java but am developing a Minecraft plugin, I need to store some data and decided a json would be the easiest since I won't have easy access to a database for the plugin.

I'm attempting to make a basic JSON to (Multidimensional) Array so that I can save my data - however all merges end up appending themselves to the top level "AreaData" tab and not properly creating the array I'm looking for.

Below is parts of the code I'm trying - wondering if a HashMap is even a good idea for this purpose

import java.util.HashMap;
public class AreaHash {
 protected HashMap<String, String> AreaData = new HashMap<String, String>();
 public AreaHash(String name, String Owner, Integer X, Integer Y, Integer Z){
 AreaData.put("Name", name);
 AreaData.put("Owner", Owner);
 AreaData.put("X", X.toString());
 AreaData.put("Y", Y.toString());
 AreaData.put("Z", Z.toString());
 }
}

AreaHash RequestedArea = new AreaHash(Name, Owner.getUniqueId().toString(), location.getBlockX(), location.getBlockY(), location.getBlockZ());
String jsonString = new Gson().toJson(RequestedArea);
DataControl.UpdateJson("raid-areas.json", jsonString);

JSON Output

{
 "AreaHash": {
 "Name": "Test",
 "Owner": "gold",
 "X": "10",
 "Y": "15",
 "Z": "-1000"
 }, 
}

What I'm actually looking to produce

{
 "1": [
 "Name": true,
 "Owner": "gold",
 "X": "10",
 "Y": "15",
 "Z": "-1000"
 ],
 "2": [
 "Name": true,
 "Owner": "silver",
 "X": "2110",
 "Y": "15",
 "Z": "-1200"
 ],
 "3": [
 "Name": true,
 "Owner": "test",
 "X": "-110",
 "Y": "70",
 "Z": "-1000"
 ],
}

• khakiout: How do you construct the object with multiple AreaHash objects?

Answer 1

You can create a Map of AreaHash objects then convert it to JSON string.

Map<String, AreaHash> data = new HashMap<>();
data.put("1", new AreaHash(...));
data.put("2", new AreaHash(...));
data.put("3", new AreaHash(...));
String jsonString = new Gson().toJson(data);
System.out.println(jsonString);

Output (Pretty printed)

{
 "1": {
 "Name": "Test",
 "Owner": "gold",
 "X": "10",
 "Y": "10",
 "Z": "0"
 },
 "2": {
 "Name": "Test",
 "Owner": "silver",
 "X": "10",
 "Y": "10",
 "Z": "-10"
 },
 "3": {
 "Name": "Test",
 "Owner": "test",
 "X": "10",
 "Y": "10",
 "Z": "-10"
 }
}

Also, take note that your desired output is not valid JSON.

[
 "Name": true,
 "Owner": "gold",
 "X": "10",
 "Y": "15",
 "Z": "-1000"
] // this will not parse