How to extract data of my simplejson array?

Question

I want to extract all the annotation of my JSONArray object and I found this post https://www.mkyong.com/java/json-simple-example-read-and-write-json/. The problem is that my JSONArray is a kind of "array of array":

[{"AnnotationOfzelda":
 [{"annotation":
  [{"duration":5000,"annotation":"salut","timestamp":2250.0}, 
   {"duration":5000,"annotation":"jp","timestamp":4570.0}]}, 
   {"duration":5000,"annotation":"asd","timestamp":3340.0}, 
   {"duration":5000,"annotation":"asd","timestamp":4040.0}]}]

I tried this code (from the post I linked)

 System.out.println(annotationJSON.toJSONString());

 Iterator<JSONObject> iterator = annotationJSON.iterator();
 while (iterator.hasNext()) {
  JSONObject factObj = (JSONObject) iterator.next();
  String annotation = (String) factObj.get("annotation");
  System.out.println(annotation);
 }

And the result is "null" and I think it's because I need to go in the array "annotation" and at the moment I'm only in "AnnotationOfzelda"

Answer 1

Try this you can use it for specific value in the JSON (annotation:"asd") or for full JSON:

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

import java.io.IOException;
import java.util.Iterator;

public class Sol {
    public static void main(String[] args) {
        String data = "[{\"AnnotationOfzelda\":\n" +
                " [{\"annotation\":\n" +
                "  [{\"duration\":5000,\"annotation\":\"salut\",\"timestamp\":2250.0}, \n" +
                "   {\"duration\":5000,\"annotation\":\"jp\",\"timestamp\":4570.0}]}, \n" +
                "   {\"duration\":5000,\"annotation\":\"asd\",\"timestamp\":3340.0}, \n" +
                "   {\"duration\":5000,\"annotation\":\"asd\",\"timestamp\":4040.0}]}]";
        ObjectMapper objectMapper = new ObjectMapper();
        JsonNode jsonNode = null;
        try {
            jsonNode = objectMapper.readTree(data);
            Iterator iterator = jsonNode.iterator();
            while (iterator.hasNext()) {
                JsonNode node = (JsonNode) iterator.next();
                if (node.get("annotation") != null) {
                    System.out.println(node.get("annotation"));
                    continue;
                }
                if (node.iterator().hasNext()) {
                    iterator = node.iterator();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Output [{"duration":5000,"annotation":"salut","timestamp":2250.0},{"duration":5000,"annotation":"jp","timestamp":4570.0}] "asd" "asd"