Yonkee Yonkee - 28 days ago 7
Java Question

How to parse nested JSON from Map<String, Object>

I am using the below to map a json response to a Map

Map<String, Object> apiResponse = restTemplate.postForObject("https://maps.googleapis.com/maps/api/geocode/json?address="+defaultLocation+"&key="+API_KEY, httpEntity, Map.class, Collections.EMPTY_MAP);


I can use the below to output the entire JSON to a string

String jsonResponse = apiResponse.get("results").toString();


However, what I want to get is a nested value which is
results->geometry->location


I have tried a number of solution with
JSONArrays, JSONObjects, Substring
but can't get them to work.

Response JSON:

{
"results" : [
{
"address_components" : [
{
"long_name" : "Auckland",
"short_name" : "Auckland",
"types" : [ "locality", "political" ]
},
{
"long_name" : "Auckland",
"short_name" : "Auckland",
"types" : [ "administrative_area_level_2", "political" ]
},
{
"long_name" : "Auckland",
"short_name" : "Auckland",
"types" : [ "administrative_area_level_1", "political" ]
},
{
"long_name" : "New Zealand",
"short_name" : "NZ",
"types" : [ "country", "political" ]
}
],
"formatted_address" : "Auckland, New Zealand",
"geometry" : {
"bounds" : {
"northeast" : {
"lat" : -36.660571,
"lng" : 175.287137
},
"southwest" : {
"lat" : -37.065475,
"lng" : 174.4438016
}
},
"location" : {
"lat" : -36.8484597,
"lng" : 174.7633315
},
"location_type" : "APPROXIMATE",
"viewport" : {
"northeast" : {
"lat" : -36.660571,
"lng" : 175.287137
},
"southwest" : {
"lat" : -37.065475,
"lng" : 174.4438016
}
}
},
"place_id" : "ChIJ--acWvtHDW0RF5miQ2HvAAU",
"types" : [ "locality", "political" ]
},
{
"address_components" : [
{
"long_name" : "Auckland",
"short_name" : "Auckland",
"types" : [ "political", "sublocality", "sublocality_level_1" ]
},
{
"long_name" : "Auckland",
"short_name" : "Auckland",
"types" : [ "locality", "political" ]
},
{
"long_name" : "Auckland",
"short_name" : "Auckland",
"types" : [ "administrative_area_level_2", "political" ]
},
{
"long_name" : "Auckland",
"short_name" : "Auckland",
"types" : [ "administrative_area_level_1", "political" ]
},
{
"long_name" : "New Zealand",
"short_name" : "NZ",
"types" : [ "country", "political" ]
},
{
"long_name" : "1010",
"short_name" : "1010",
"types" : [ "postal_code" ]
}
],
"formatted_address" : "Auckland, 1010, New Zealand",
"geometry" : {
"bounds" : {
"northeast" : {
"lat" : -36.8364659,
"lng" : 174.7838398
},
"southwest" : {
"lat" : -36.8621041,
"lng" : 174.7503805
}
},
"location" : {
"lat" : -36.8484597,
"lng" : 174.7633315
},
"location_type" : "APPROXIMATE",
"viewport" : {
"northeast" : {
"lat" : -36.8364659,
"lng" : 174.7838398
},
"southwest" : {
"lat" : -36.8621041,
"lng" : 174.7503805
}
}
},
"place_id" : "ChIJuZqpSPtHDW0R4LOiQ2HvAAU",
"types" : [ "political", "sublocality", "sublocality_level_1" ]
}
],
"status" : "OK"
}


Any help would be greatly appreciated.

Answer
JSONObject obj=new JSONObject(jsonresult);
// get result array
JSONArray resultsarray= obj.getJSONArray("results"); 
for (int i=0;i<resultsarray.length(),i++){
        // get Objects using index
        JSONObject jsonobject= results.getJSONObject(i);
        // get geometry object
        JSONObject geometry= jsonobject.getJSONObject("geometry");
        // get location object from geometry
        JSONObject location= geometry.getJSONObject("location");

        // get location values from location object
        double lat = location.optDouble("lat",0.0);
        double long = location.optDouble("lng",0.0);
 }

About optDouble

public double optDouble(String key, double defaultValue) {

Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.