org.json.JSONException: JSONObject["status"] is not a JSONObject

Question

I am now currently using a weather API from http://wiki.swarma.net/index.php?title=%E5%BD%A9%E4%BA%91%E5%A4%A9%E6%B0%94API/v2 and wished to convert the JSONObject into printable Strings. However, when I am working on the following code, two errors occurred:

public class getApi {
    private static final String WEATHER_MAP_URL = "https://api.caiyunapp.com/v2/TAkhjf8d1nlSlspN/121.6544,25.1552/realtime.json";
    private static final String WEATHER_TEST_API = "TAkhjf8d1nlSlspN";

    public static JSONObject getWeatherJson() {
        try {
            URL url = new URL( WEATHER_MAP_URL );
            HttpURLConnection connection =
                    (HttpURLConnection)url.openConnection();

            connection.addRequestProperty( "x-api-key", WEATHER_TEST_API );
            BufferedReader reader = new BufferedReader(
                    new InputStreamReader( connection.getInputStream()) );

            StringBuffer json = new StringBuffer( 1024 );
            String tmp;
            while( (tmp = reader.readLine()) != null )
                json.append(tmp).append("\n");
            reader.close();

            JSONObject data = new JSONObject( json.toString() );
            if(data.getJSONObject("status").toString() != "ok" ) {
                return null;
            }
            return data;       
        }
        catch(Exception e) {
            e.printStackTrace();
            return null;
        }
    }
    public static void main( String[] args ) {
        JSONObject WeatherJson = getWeatherJson();
        try {
            JSONArray details = WeatherJson.getJSONObject("result").getJSONObject("hourly").
                    getJSONArray("skycon");
            System.out.println(details.getJSONObject(0).getJSONObject("value").toString());
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

The JSONObject structure, which is also shown in the link above, is like this:

{
    "status":"ok",
    "lang":"zh_CN", 
    "server_time":1443418212,
    "tzshift":28800, 
    "location":[
        25.1552, //latitude
        121.6544 //longitude
    ],
    "unit":"metric", 
    "result":{
        "status":"ok",
        "hourly":{ 
            "status":"ok",
            "skycon":[ 
                {
                    "value":"Rain",
                    "datetime":"2015-09-28 13:00"
                },
                {
                 ...
                }]
           }
      }
}

The error occurred:

org.json.JSONException: JSONObject["status"] is not a JSONObject.
    at org.json.JSONObject.getJSONObject(JSONObject.java:557)
    at getApi.getWeatherJson(getApi.java:34)
    at getApi.main(getApi.java:45)
Exception in thread "main" java.lang.NullPointerException
    at getApi.main(getApi.java:47)

I have looked at similar posts on the topic is not a JSONObject Exception but found that none of them can help me. I suspect that something is wrong with requesting the data, so actually, getWeatherJson() returns a null object and results in the NullPointerException and JSONObjectException.

Can anyone help me with the code?

Solution 1

According to the getJSONObject() Javadoc, this method will throw an exception if the returned object isn't a true JSON object, which it isn't because "status" is a string. As such, try using data.getString("status").

Solution 2

The status field in the JSON document you have posted is not an object. In JSON, objects are enclosed in with {} brackets. The result node however, is a nested object which holds the status key/value pair. Try the following:

JSONObject data = new JSONObject(json.toString());
  if(data.getJSONObject("result").get("status").toString() != "ok" ) {
    return null;
  }

Comments

[Z.Richard]

Appreciate your help as well!