有没有一个简单的json函数可以从jsonobject中获取所有的键？

import org.json.JSONObject;
import java.util.Iterator;

public class Main {
    public static void main(String[] args) {
        String jsonString = "{\"key1\":\"value1\",\"key2\":\"value2\",\"key3\":\"value3\"}";
        JSONObject jsonObject = new JSONObject(jsonString);

        Iterator<String> keys = jsonObject.keys();
        while (keys.hasNext()) {
            String key = keys.next();
            System.out.println("Key: " + key);
        }
    }
}