1, import dependence

<dependency>
  	 <groupId>org.json</groupId>
     <artifactId>json</artifactId>
     <version>20180130</version>
</dependency>

2, write test class

import org.json.JSONArray;
import org.json.JSONObject;

The // JSON object is added to the key value pair, and the JSONARRAY is added to the JSON object.
public class Test {
	public static void main(String[] args) {
		JSONObject jsonObject = new JSONObject();
		JSONArray jsonArray = new JSONArray();

		jsonObject.put("key", "value");// JSONObject object Add key value pair
		jsonArray.put(jsonObject);// Add JSONOBJECT object to the JSON array
		System.out.println(jsonObject);
		System.out.println("--------------------------------------");
		System.out.println(jsonArray);
		System.out.println("------------------tostring--------------------");
		System.out.println(jsonObject.toString());
		System.out.println("--------------------------------------");
		System.out.println(jsonArray.toString());
	}
}

Console output: