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 !!!

azurefrog · Accepted Answer · 2014-04-23 17:07:09Z

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);

answered Apr 23, 2014 at 17:07

azurefrog

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1 Comment

user3565584 Over a year ago

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

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