Parsing Nested JSON in java without know structure of JSON?

Question

I am Trying to parse nested JSON, But i don't know the format of JSON...I want all the Keys and Values of JSON.

Example:

{
    "txnSpecificData1": "11",
    "txnSpecificData2": "21",
    "merchantData": {
        "merchantSpecificData1": "111",
        "merchantSpecificData2": "222",
        "merchantSpecificData3": {
            "data1": "1",
            "data2": "2"
        }
    }
}

Now I want all Keys and their Values...I tried JSONParser but it is not giving all keys. Please some one guide me to do this.

I need value based on key.. Let's say If i give key as "merchantSpecificData2" it should return me value.

O/P should be MAP with all Key and Values:

OutPut Map : : : {txnSpecificData1=11, txnSpecificData1=22, merchantSpecificData1=111, merchantSpecificData2=222,data1=1,data2=2}

Answer 1

Please refer this

Sample Code

public static void main(String[] args) throws JSONException {
        String json = "{\"txnSpecificData1\": \"11\",\"txnSpecificData2\": \"21\",\"merchantData\": {\"merchantSpecificData1\": \"111\",\"merchantSpecificData2\": \"222\",\"merchantSpecificData3\": {\"data1\": \"1\",\"data2\": \"2\"}}}";

        JSONObject jsonObject = new JSONObject(json);
        JSONObject merchantData = (JSONObject) jsonObject.get("merchantData");
        System.out.println(merchantData.get("merchantSpecificData2"));
    }

Output

222

Jar

Maven

Refer hew for more details.

Answer 2

A iterative solution to store all keys and respective value into a map. Note, all exception scenarios are not handled.

public static void main(String[] args) throws Exception{
    JSONObject jo = new JSONObject(your_json_String_here);
    Map<String, String> map = new HashMap<String, String>(); 
    new Test().iterateJson(jo, map);
    System.out.println(map);
}
public void iterateJson(JSONObject jo, Map map) {
    for(Object o : jo.keySet()){
        if(jo.get(o.toString()) instanceof JSONObject) 
            iterateJson(jo.getJSONObject(o.toString()), map);
        else
            map.put(o.toString(), jo.get(o.toString()));
    }
}

Answer 3

You can use http://json-lib.sourceforge.net/apidocs/net/sf/json/package-summary.html for parsing the JSON. Using JSONSerializer you can get a JSONObject parsing your string. Then methods available in JSONObject will give you all keys and values. Value can be simple like String/Long/Boolean or complex like another JSONObject/JSONArray.

Answer 4

Here is the solution..

private static HashMap print(final JsonNode node) throws IOException {
        HashMap map = new HashMap();
        Iterator<Map.Entry<String, JsonNode>> fieldsIterator = node.getFields();

        while (fieldsIterator.hasNext()) {
            Map.Entry<String, JsonNode> field = fieldsIterator.next();
            final String key = field.getKey();

            final JsonNode value = field.getValue();
            if (value.isContainerNode()) {
                print(value);
            } else {
                map.put(key, value);
            }
        }
        return map;
    }