Convert JSONObject to Map

Question

I have a JSONObject with some attributes that I want to convert into a Map lt String  Object gt   Is there something that I can use from the json org or ObjectMapper

User · Answer

Found out these problems can be addressed by using

ObjectMapper#convertValue(Object fromValue, Class<T> toValueType)

As a result, the origal quuestion can be solved in a 2-step converison:

Demarshall the JSON back to an object - in which the Map<String, Object> is demarshalled as a HashMap<String, LinkedHashMap>, by using bjectMapper#readValue().
Convert inner LinkedHashMaps back to proper objects

ObjectMapper mapper = new ObjectMapper(); Class clazz = (Class) Class.forName(classType); MyOwnObject value = mapper.convertValue(value, clazz);

To prevent the 'classType' has to be known in advance, I enforced during marshalling an extra Map was added, containing <key, classNameString> pairs. So at unmarshalling time, the classType can be extracted dynamically.

User · Answer

org json JSONObject toMap   will do to work

User · Answer

Note to the above solution  from A Paul   The solution doesn t work  cause it doesn t reconstructs back a HashMap lt  String  Object   - instead it creates a HashMap lt  String  LinkedHashMap     Reason why is because during demarshalling  each Object  JSON marshalled as a LinkedHashMap  is used as-is  it takes 1-on-1 the LinkedHashMap  instead of converting the LinkedHashMap back to its proper Object    If you had a HashMap lt  String  MyOwnObject   then proper demarshalling was possible - see following example   ObjectMapper mapper   new ObjectMapper    TypeFactory typeFactory   mapper getTypeFactory    MapType mapType   typeFactory constructMapType HashMap class  String class  MyOwnObject class   HashMap lt String  MyOwnObject gt  map   mapper readValue new StringReader hashTable toString     mapType

User · Answer

use Jackson  https   github com FasterXML jackson  from http   json org  HashMap lt String Object gt  result          new ObjectMapper   readValue  lt JSON OBJECT gt   HashMap class

User · Answer

The best way to convert it to HashMap lt String  Object gt  is this   HashMap lt String  Object gt  result   new ObjectMapper   readValue jsonString  new TypeReference lt Map lt String  Object gt  gt

User · Answer

You can use Gson    com google gson  library if you find any difficulty using Jackson   HashMap lt String  Object gt  yourHashMap   new Gson   fromJson yourJsonObject toString    HashMap class

User · Answer

This is what worked for me       public static Map lt String  Object gt  toMap JSONObject jsonobj   throws JSONException           Map lt String  Object gt  map   new HashMap lt String  Object gt             Iterator lt String gt  keys   jsonobj keys            while keys hasNext                  String key   keys next                Object value   jsonobj get key               if  value instanceof JSONArray                    value   toList  JSONArray  value                 else if  value instanceof JSONObject                    value   toMap  JSONObject  value                                map put key  value               return map             public static List lt Object gt  toList JSONArray array  throws JSONException           List lt Object gt  list   new ArrayList lt Object gt             for int i   0  i  lt  array length    i                  Object value   array get i               if  value instanceof JSONArray                    value   toList  JSONArray  value                             else if  value instanceof JSONObject                    value   toMap  JSONObject  value                             list add value               return list      Most of this is from this question  How to convert JSONObject to new Map for all its keys using iterator java

[java] Convert JSONObject to Map

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