在Java中读取具有多个对象的json文件

Question

I have written a program that reads a simple json file:

public static void main(String[] args) {
    JSONParser parser = new JSONParser();
    try {
        JSONArray a = (JSONArray) parser.parse(new FileReader("C:/Users/Zonoid/Desktop/EQ.json"));
        for (Object o : a)
        {
            JSONObject obj = (JSONObject) o;
            String city = (String) obj.get("CITY");
            System.out.println("City : " + city);
            String loc = (String) obj.get("LOCATION");
            System.out.println("Location : " + loc);
            long el = (Long) obj.get("E_LEVEL");
            System.out.println("Emergency Level : " + el);
            long depth = (Long) obj.get("DEPTH");
            System.out.println("Depth : " + depth);
            long i = (Long) obj.get("INTENSITY");
            System.out.println("Intensity :"+i);
            System.out.println("\n");
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (ParseException e) {
        e.printStackTrace();
    }
}

with my json file being:

[{"CITY":"MUMBAI","LOCATION":"a" ,"E_LEVEL": 6,"DEPTH":10,"INTENSITY":5},
{"CITY":"MUMBAI","LOCATION":"b" ,"E_LEVEL": 8,"DEPTH":20,"INTENSITY":4},
{"CITY":"MUMBAI","LOCATION":"c" ,"E_LEVEL": 3,"DEPTH":13,"INTENSITY":5},
{"CITY":"MUMBAI","LOCATION":"d" ,"E_LEVEL": 6,"DEPTH":12,"INTENSITY":4},]

I am working on a project that deals with earthquake alerts and want to read their JSON files however I cannot import them in JSON Array. The file I want to import looks like this:

{
  "type": "FeatureCollection",
  "metadata": {
    "generated": 1488472809000,
    "url": "https:\/\/earthquake.usgs.gov\/earthquakes\/feed\/v1.0\/summary\/significant_week.geojson",
    "title": "USGS Significant Earthquakes, Past Week",
    "status": 200,
    "api": "1.5.4",
    "count": 2
  },
  "features": [
    {
      "type": "Feature",
      "properties": {
        "mag": 5.5,
        "place": "42km WSW of Anchor Point, Alaska",
        "time": 1488420690658,....

Please tell what changes should be made.

Answer 1

If you are trying to read from features only, first you need to read the whole file as an object. Then you can, read the array part in the following way:

Object object = parser.parse(new FileReader("C:/Users/Zonoid/Desktop/EQ.json"));
JSONObject jasonObject = (JSONObject) object;
JSONArray features = (JSONArray) jasonObject.get("features");