How to iterate or loop through JSON array in Java

By Abhi Tiwari

In this tutorial, we will learn how to iterate a JSON array in Java with the code and Explanation using json-simple-1.1.1.jar.

What is a JSON array?

• It represents a list of ordered values.
• Stores several values separated with commas (,).
• It stores the number, string, boolean, or object.
• [] (square bracket) represents JSON Array.

Prerequisite

You have to download json-simple-1.1.1.jar Version 1.1.1 from here.

Click here to directly download json-simple-1.1.1.jar 

After download, the json-simple-1.1.1.jar add the .jar file to your IDE. Example NetBeans, etc.

A simple JSON file as an example

Here we already have a Detail.json file that contains an array of names.

Detail.json

Java program to iterate or loop through JSON array

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

public class IterateJsonExample {

    public static void main(String[] args) {
        JSONParser jsonParserObj = new JSONParser();
        try {
            JSONObject jsonObj = (JSONObject) jsonParserObj.parse(new FileReader("E://Detail.json"));

            System.out.println("Names are : ");
            JSONArray jsonArrObj = (JSONArray) jsonObj.get("Names");

            Iterator<String> iteratorObj = jsonArrObj.iterator();
            while (iteratorObj.hasNext()) {
                System.out.println(iteratorObj.next());
            }

        } catch (FileNotFoundException ex) {
            ex.printStackTrace();
        } catch (IOException ex) {
            ex.printStackTrace();
        } catch (ParseException ex) {
            ex.printStackTrace();
        }
    }
}

Output:

Names are : 
Aman
Namita
Piyush
Priyansh
kartik
Adarsh

Explanation

• Line 13: Here we created an object named jsonParserObj of JSONParser class to read the JSON file.
• Line 15: In try block,we using the jsonParserObj.parse() method and the FileReader class we read the JSON file and store it in jsonObj of the JSONObject.
• Line 18: Using the jsonObj.get() method, we get our array of names and stores in the JSONArray object known as jsonArrObj.
• Line 20 – 23: By using the jsonArrObj.iterator() method we store the values of jsonArrObj and in a while loop using the iteratorObj.next() that returns the value and simply we print that values.

That’s enough for an overview of how to iterate or loop through JSON array.