Parsing JSON pada Java tanpa mengetahui format JSON

public void parse(String json)  {
       JsonFactory factory = new JsonFactory();

       ObjectMapper mapper = new ObjectMapper(factory);
       JsonNode rootNode = mapper.readTree(json);  

       Iterator<Map.Entry<String,JsonNode>> fieldsIterator = rootNode.fields();
       while (fieldsIterator.hasNext()) {

           Map.Entry<String,JsonNode> field = fieldsIterator.next();
           System.out.println("Key: " + field.getKey() + "\tValue:" + field.getValue());
       }
}

JSONObject object = new JSONObject(myJSONString);
String[] keys = JSONObject.getNames(object);

for (String key : keys)
{
    Object value = object.get(key);
    // Determine type of value and do something with it...
}

public class JsonParsing {
static JsonParser parser = new JsonParser();

public static HashMap<String, Object> createHashMapFromJsonString(String json) {

    JsonObject object = (JsonObject) parser.parse(json);
    Set<Map.Entry<String, JsonElement>> set = object.entrySet();
    Iterator<Map.Entry<String, JsonElement>> iterator = set.iterator();
    HashMap<String, Object> map = new HashMap<String, Object>();

    while (iterator.hasNext()) {

        Map.Entry<String, JsonElement> entry = iterator.next();
        String key = entry.getKey();
        JsonElement value = entry.getValue();

        if (null != value) {
            if (!value.isJsonPrimitive()) {
                if (value.isJsonObject()) {

                    map.put(key, createHashMapFromJsonString(value.toString()));
                } else if (value.isJsonArray() && value.toString().contains(":")) {

                    List<HashMap<String, Object>> list = new ArrayList<>();
                    JsonArray array = value.getAsJsonArray();
                    if (null != array) {
                        for (JsonElement element : array) {
                            list.add(createHashMapFromJsonString(element.toString()));
                        }
                        map.put(key, list);
                    }
                } else if (value.isJsonArray() && !value.toString().contains(":")) {
                    map.put(key, value.getAsJsonArray());
                }
            } else {
                map.put(key, value.getAsString());
            }
        }
    }
    return map;
}
}

public static JsonParser parser = new JsonParser();
public static void main(String args[]) {
     writeJson("JsonFile.json");
     readgson("JsonFile.json");
}
public static void readgson(String file) {
    try {
        System.out.println( "Reading JSON file from Java program" );

        FileReader fileReader = new FileReader( file );
        com.google.gson.JsonObject object = (JsonObject) parser.parse( fileReader );

        Set <java.util.Map.Entry<String, com.google.gson.JsonElement>> keys = object.entrySet();
        if ( keys.isEmpty() ) {
            System.out.println( "Empty JSON Object" );
        }else {
            Map<String, Object> map = json_UnKnown_Format( keys );
            System.out.println("Json 2 Map : "+map);
        }

    } catch (IOException ex) {
        System.out.println("Input File Does not Exists.");
    }
}
public static Map<String, Object> json_UnKnown_Format( Set <java.util.Map.Entry<String, com.google.gson.JsonElement>> keys ){
    Map<String, Object> jsonMap = new HashMap<String, Object>();
    for (Entry<String, JsonElement> entry : keys) {
        String keyEntry = entry.getKey();
        System.out.println(keyEntry + " : ");
        JsonElement valuesEntry =  entry.getValue();
        if (valuesEntry.isJsonNull()) {
            System.out.println(valuesEntry);
            jsonMap.put(keyEntry, valuesEntry);
        }else if (valuesEntry.isJsonPrimitive()) {
            System.out.println("P - "+valuesEntry);
            jsonMap.put(keyEntry, valuesEntry);
        }else if (valuesEntry.isJsonArray()) {
            JsonArray array = valuesEntry.getAsJsonArray();
            List<Object> array2List = new ArrayList<Object>();
            for (JsonElement jsonElements : array) {
                System.out.println("A - "+jsonElements);
                array2List.add(jsonElements);
            }
            jsonMap.put(keyEntry, array2List);
        }else if (valuesEntry.isJsonObject()) {             
             com.google.gson.JsonObject obj = (JsonObject) parser.parse(valuesEntry.toString());                    
             Set <java.util.Map.Entry<String, com.google.gson.JsonElement>> obj_key = obj.entrySet();
             jsonMap.put(keyEntry, json_UnKnown_Format(obj_key));
        }
    }
    return jsonMap;
}
@SuppressWarnings("unchecked")
public static void writeJson( String file ) {

    JSONObject json = new JSONObject();

    json.put("Key1", "Value");
    json.put("Key2", 777); // Converts to "777"
    json.put("Key3", null);
    json.put("Key4", false);

        JSONArray jsonArray = new JSONArray();
        jsonArray.put("Array-Value1");
        jsonArray.put(10); 
        jsonArray.put("Array-Value2");

    json.put("Array : ", jsonArray); // "Array":["Array-Value1", 10,"Array-Value2"]

        JSONObject jsonObj = new JSONObject();
        jsonObj.put("Obj-Key1", 20);
        jsonObj.put("Obj-Key2", "Value2");
        jsonObj.put(4, "Value2"); // Converts to "4"

    json.put("InnerObject", jsonObj);

        JSONObject jsonObjArray = new JSONObject();
            JSONArray objArray = new JSONArray();
            objArray.put("Obj-Array1");
            objArray.put(0, "Obj-Array3");
        jsonObjArray.put("ObjectArray", objArray);

    json.put("InnerObjectArray", jsonObjArray);

        Map<String, Integer> sortedTree = new TreeMap<String, Integer>();
        sortedTree.put("Sorted1", 10);
        sortedTree.put("Sorted2", 103);
        sortedTree.put("Sorted3", 14);

    json.put("TreeMap", sortedTree);        

    try {
        System.out.println("Writting JSON into file ...");
        System.out.println(json);
        FileWriter jsonFileWriter = new FileWriter(file);
        jsonFileWriter.write(json.toJSONString());
        jsonFileWriter.flush();
        jsonFileWriter.close();
        System.out.println("Done");

    } catch (IOException e) { 
        e.printStackTrace();
    }

}

JsonReader.jsonToMaps(String json)

JsonReader.jsonToJava(String json) 

JsonWriter.objectToJson(MyClass foo).

ObjectMapper objectMapper = new ObjectMapper();
Map<String, Object> map = objectMapper.readValue(jsonString, new TypeReference<HashMap<String,Object>>(){});

JsonNode jsonNode = objectMapper.readTree(String jsonString) 

public class JsonParser {

    public static Object parseAndMess(Object object) throws IOException {
        String json = JsonUtil.toJson(object);
        JsonNode jsonNode = parseAndMess(json);
        if(null != jsonNode)
            return JsonUtil.toObject(jsonNode, object.getClass());

        return null;
    }

    public static JsonNode parseAndMess(String json) throws IOException {
        JsonNode rootNode = parse(json);
        return mess(rootNode, new Random());
    }

    private static JsonNode parse(String json) throws IOException {
        JsonFactory factory = new JsonFactory();
        ObjectMapper mapper = new ObjectMapper(factory);
        JsonNode rootNode = mapper.readTree(json);
        return rootNode;

    }

    private static JsonNode mess(JsonNode rootNode, Random rand) throws IOException {
        if (rootNode instanceof ObjectNode) {
            Iterator<Map.Entry<String, JsonNode>> fieldsIterator = rootNode.fields();
            while (fieldsIterator.hasNext()) {
                Map.Entry<String, JsonNode> field = fieldsIterator.next();
                replaceObjectNode((ObjectNode) rootNode, field, rand);
            }
        } else if (rootNode instanceof ArrayNode) {
            ArrayNode arrayNode = ((ArrayNode) rootNode);
            replaceArrayNode(arrayNode, rand);
        }
        return rootNode;
    }

    private static void replaceObjectNode(ObjectNode rootNode, Map.Entry<String, JsonNode> field, Random rand)
            throws IOException {
        JsonNode childNode = field.getValue();
        if (childNode instanceof IntNode) {
            (rootNode).put(field.getKey(), rand.nextInt(1000));
        } else if (childNode instanceof LongNode) {
            (rootNode).put(field.getKey(), rand.nextInt(1000000));
        } else if (childNode instanceof FloatNode) {
            (rootNode).put(field.getKey(), format(rand.nextFloat()));
        } else if (childNode instanceof DoubleNode) {
            (rootNode).put(field.getKey(), format(rand.nextFloat()));
        } else {
            mess(childNode, rand);
        }
    }

    private static void replaceArrayNode(ArrayNode arrayNode, Random rand) throws IOException {
        int arrayLength = arrayNode.size();
        if(arrayLength == 0)
            return;
        if (arrayNode.get(0) instanceof IntNode) {
            for (int i = 0; i < arrayLength; i++) {
                arrayNode.set(i, new IntNode(rand.nextInt(10000)));
            }
        } else if (arrayNode.get(0) instanceof LongNode) {
            arrayNode.removeAll();
            for (int i = 0; i < arrayLength; i++) {
                arrayNode.add(rand.nextInt(1000000));
            }
        } else if (arrayNode.get(0) instanceof FloatNode) {
            arrayNode.removeAll();
            for (int i = 0; i < arrayLength; i++) {
                arrayNode.add(format(rand.nextFloat()));
            }
        } else if (arrayNode.get(0) instanceof DoubleNode) {
            arrayNode.removeAll();
            for (int i = 0; i < arrayLength; i++) {
                arrayNode.add(format(rand.nextFloat()));
            }
        } else {
            for (int i = 0; i < arrayLength; i++) {
                mess(arrayNode.get(i), rand);
            }
        }
    }

    public static void print(JsonNode rootNode) throws IOException {
        System.out.println(rootNode.toString());
    }

    private static double format(float a) {
        return Math.round(a * 10000.0) / 100.0;
    }
}