Convert from LinkedHashMap to Json String

Question

I\'m Workin with Mongo using Jongo, when I do a query I receive a LinkedHashMap as result.

Iterator one = (Iterator) friends.find(query).project         


        

Answer 1

If you have access to some JSON library, it seems like that's the way to go.

If using org.json library, use public JSONObject(java.util.Map map):

String jsonString = new JSONObject(data).toString()

If Gson, use the gson.toJson() method mentioned by @hellboy:

String jsonString = new Gson().toJson(data, Map.class);

Answer 2

I resolved the problem using the following code:

    Iterator one = (Iterator) friends.find(query).projection("{_id:0}").as(Object.class);
    while (one.hasNext()) {
        Map data= new HashMap();

        data= (HashMap) one.next();
        JSONObject d = new JSONObject();
        d.putAll(data);
        String content=d.toString();
    }

Answer 3

You can use Gson library from Google to convert any object to JSON. Here is an example to convert LinkedHashMap to json -

Gson gson = new Gson();
String json = gson.toJson(map,LinkedHashMap.class);

Answer 4

One of the com.mongodb.BasicDBObject constructors takes a Map as input. Then you just have to call the toString() on the BasicDBObject object.

Iterator one = (Iterator) friends.find(query).projection("{_id:0}").as(Object.class);
    while (one.hasNext()) {
        LinkedHashMap data= new LinkedHashMap();

        data= (LinkedHashMap) one.next();

        com.mongodb.BasicDBObject bdo = new com.mongodb.BasicDBObject(data);    
        String json = bdo.toString();
    }