Creating JSON document using foreach loop

Question

I am trying to fetch the data from the database and then trying to set the values in the JSON document using ArrayList but i am not able to do that. Lets say this is hard code JSON which i want to convert it into dynamic JSON view plainprint? Note: Text content in the code blocks is automatically word-wrapped

String json = "{ \"demo\":[[ \"Sam\",\"Sola\",\"Accun\"],[\"Raj\",\"Sanjosh\",\"CA\"],[\"Karan\",\"Toshi\",\"Java\"]]}"; 

Now, to embed the JSON rows dynamically , i have used ArrayList as follows : view plainprint? Note: Text content in the code blocks is automatically word-wrapped

ArrayList<Object> al = new ArrayList<Object>(); 
.............some database code.......... 
while (result.next()) { 
al.add("[ \"" + result.getString(1) + "\", 
 \""+ result.getString(3) + "\", 
 \"" + result.getString(4)+ "\", 
 \"" + result.getString(5) + "\", 
 \""+ result.getString(6) + "\", 
 \"" + result.getString(7)+ "\", 
 \"" + result.getString(8) + "\"]"); 
} 

Now i want to embed this collection into the JSON document. but not sure how to do this. view plainprint? Note: Text content in the code blocks is automatically word-wrapped

 String h = "{ \"demo\":[ "+ 
 for(Object o : al){ 
 } 
 +"]}"; 

Please Guide me to get through this....Thanks !!!

Answer 1

Instead of manually trying to construct the json, you would be better off using one of the existing libraries. It looks like the json you are trying to generate is a simple mapping, so you could do something like this:

 List<String> list = new ArrayList<String>();
 list.add(result.getString(1));
 list.add(result.getString(3));
 //etc
 Map<String, List<String>> map = new HashMap<String, List<String>>();
 map.put("demo", list);
 String json = new Gson().toJson(map);

• user3565584: wow..thanks..never thought Map can be implemented this way...Thanks for the Heads Up dear...shall try to implement this code...Cheers!!