Question 216485 in Json Question posted in
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How to parse JSONArray to JSON fields?

As shown in title, I want to convert JSONArray (defined in "splits" field) to JSON fields using Java. I couldn’t find a similar topic here, if I missed something please let me know.

Bit of my JSON is shown below:

{
  "carId": 1001,
  "driverIndex": 0,
  "laptime": 173001,
  "isValidForBest": false,
  "splits": [
    91851,
    52002,
    29147
  ]
},
{
  "carId": 1001,
  "driverIndex": 0,
  "laptime": 107270,
  "isValidForBest": true,
  "splits": [
    26295,
    51960,
    29015
  ]
}

I want to achieve something like this:

{
  "carId": 1001,
  "driverIndex": 0,
  "laptime": 173001,
  "isValidForBest": false,
  "sector1": 91851,
  "sector2": 52002,
  "sector3": 29147
},
{
  "carId": 1001,
  "driverIndex": 0,
  "laptime": 107270,
  "isValidForBest": true,
  "sector1": 26295,
  "sector2": 51960,
  "sector3": 29015
}

I found some ways to solve it by parsing array to a new object, but I don’t want to create it if possible, because another object would make further code much more complicated and I want it to be as simple as possible. Values in "splits" field are also not used anywhere else.

I tried using JsonNode and ObjectNode from package com.fasterxml.jackson.databind, but there were problems with converting from ArrayNode to ObjectNode and nothing found on web was helpful.

Tags:

2

Answers


  1. 0

    You can iterate through the JSONArray, extract the individual values, and add them as separate fields in the existing JSON objects:

    import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JSONArrayToJSONFields {
    public static void main(String[] args) {
        String jsonInput = "{n" +
                "  "carId": 1001,n" +
                "  "driverIndex": 0,n" +
                "  "laptime": 173001,n" +
                "  "isValidForBest": false,n" +
                "  "splits": [n" +
                "    91851,n" +
                "    52002,n" +
                "    29147n" +
                "  ]n" +
                "}";

        ObjectMapper mapper = new ObjectMapper();
        try {
            JsonNode rootNode = mapper.readTree(jsonInput);
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  2. 0

    assuming that the input is an Array of cards

    JsonNode root = new ObjectMapper().readTree(jsonString);
root.forEach(
        card -> {
            ObjectNode cardObject = (ObjectNode) card;
            ArrayNode splits = (ArrayNode) cardObject.remove("splits");
            for(int i=0; i < splits.size(); i++) {
                cardObject.put("sector"+i, splits.get(i));
            }
        }
);
return root;
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