Retrieving values from nested JSON Object

Question

I ve got JSON file  which I want to parse  The JSON file   myfile   has format as follows          LanguageLevels              1    Poczatkujacy            2    SrednioZaawansowany            3    Zaawansowany            4    Ekspert            I want to retrieve value  SrednioZaawansowany  of Key 2 from Language Levels   import java io FileNotFoundException  import java io FileReader  import java io IOException  import java util Iterator  import org json simple JSONArray  import org json simple JSONObject  import org json simple parser JSONParser  import org json simple parser ParseException   public class JsonSimpleExample   public static void main String   args     JSONParser parser   new JSONParser     try        Object obj   parser parse new FileReader  myfile         JSONObject jsonObject    JSONObject  obj      JSONObject jsonChildObject    JSONObject jsonObject get  LanguageLevels      What to do next  How I can iterate over it

User · Answer

You will have to iterate step by step into nested JSON.

for e.g a JSON received from Google geocoding api

{
   "results" : [
      {
         "address_components" : [
            {
               "long_name" : "Bhopal",
               "short_name" : "Bhopal",
               "types" : [ "locality", "political" ]
            },
            {
               "long_name" : "Bhopal",
               "short_name" : "Bhopal",
               "types" : [ "administrative_area_level_2", "political" ]
            },
            {
               "long_name" : "Madhya Pradesh",
               "short_name" : "MP",
               "types" : [ "administrative_area_level_1", "political" ]
            },
            {
               "long_name" : "India",
               "short_name" : "IN",
               "types" : [ "country", "political" ]
            }
         ],
         "formatted_address" : "Bhopal, Madhya Pradesh, India",
         "geometry" : {
            "bounds" : {
               "northeast" : {
                  "lat" : 23.3326697,
                  "lng" : 77.5748062
               },
               "southwest" : {
                  "lat" : 23.0661497,
                  "lng" : 77.2369767
               }
            },
            "location" : {
               "lat" : 23.2599333,
               "lng" : 77.412615
            },
            "location_type" : "APPROXIMATE",
            "viewport" : {
               "northeast" : {
                  "lat" : 23.3326697,
                  "lng" : 77.5748062
               },
               "southwest" : {
                  "lat" : 23.0661497,
                  "lng" : 77.2369767
               }
            }
         },
         "place_id" : "ChIJvY_Wj49CfDkR-NRy1RZXFQI",
         "types" : [ "locality", "political" ]
      }
   ],
   "status" : "OK"
}

I shall iterate in below given fashion to "location" : { "lat" : 23.2599333, "lng" : 77.412615

//recieve JSON in json object

        JSONObject json = new JSONObject(output.toString());
        JSONArray result = json.getJSONArray("results");
        JSONObject result1 = result.getJSONObject(0);
        JSONObject geometry = result1.getJSONObject("geometry");
        JSONObject locat = geometry.getJSONObject("location");

        //"iterate onto level of location";

        double lat = locat.getDouble("lat");
        double lng = locat.getDouble("lng");

User · Answer

Maybe you re not using the latest version of a JSON for Java Library   json-simple has not been updated for a long time  while JSON-Java was updated 2 month ago    JSON-Java can be found on GitHub  here is the link to its repo  https   github com douglascrockford JSON-java  After switching the library  you can refer to my sample code down below   public static void main String   args        String JSON       LanguageLevels      1     Pocz  u0105tkuj  u0105cy     2       u015arednioZaawansowany     3     Zaawansowany     4     Ekspert     n        JSONObject jsonObject   new JSONObject JSON       JSONObject getSth   jsonObject getJSONObject  LanguageLevels        Object level   getSth get  2         System out println level       And as JSON-Java open-sourced  you can read the code and its document  they will guide you through   Hope that it helps

User · Answer

Try this  you can parse nested JSON public static String getJsonValue String jsonReq  String key            JSONObject json   new JSONObject jsonReq           boolean exists   json has key           Iterator lt   gt  keys          String nextKeys          String val    quot  quot           if   exists                keys   json keys                while  keys hasNext                      nextKeys    String  keys next                    try                       if  json get nextKeys  instanceof JSONObject                            return getJsonValue json getJSONObject nextKeys  toString    key                         else if  json get nextKeys  instanceof JSONArray                            JSONArray jsonArray   json getJSONArray nextKeys                           int i   0                          if  i  lt  jsonArray length    do                               String jsonArrayString   jsonArray get i  toString                                JSONObject innerJson   new JSONObject jsonArrayString                               return getJsonValue innerJson toString   key                             while  i  lt  jsonArray length                                             catch  Exception e                        e printStackTrace                                              else               val   json get key  toString                      return val

User · Answer

You can see that JSONObject extends a HashMap  so you can simply use it as a HashMap   JSONObject jsonChildObject    JSONObject jsonObject get  LanguageLevels    for  Map Entry in jsonChildOBject entrySet          System out println  Key       entry getKey        Value       entry getValue

User · Answer

To see all keys of Jsonobject use this      String JSON       LanguageLevels      1     Pocz  u0105tkuj  u0105cy     2       u015arednioZaawansowany     3     Zaawansowany     4     Ekspert     n       JSONObject obj   new JSONObject JSON       Iterator iterator   obj keys        String key   null      while  iterator hasNext              key    String  iterator next            System out pritnln key

User · Answer

JSONArray jsonChildArray    JSONArray  jsonChildArray get  LanguageLevels        JSONObject secObject    JSONObject  jsonChildArray get 1     I think this should work  but i do not have the possibility to test it at the moment

[java] Retrieving values from nested JSON Object

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