java servlet按月份名称对json数据进行排序

Question

I have a json array having single object with key as month name. When coming from Db it looks like [{ "January": "January", "February": "February", "March": "March", "April": "April", "May": "May", "June": "June", "July": "July", "August": "August", "September": "September", "October": "October", "November": "November", "December": "December" }] and on frontend it looks like

<select data-field-id="317" class="form-control selectchange to_month" id="searchform_to_month" name="searchform_to_month"><option value="">Select To Month</option><option value="June">June</option><option value="October">October</option><option value="December">December</option><option value="May">May</option><option value="September">September</option><option value="March">March</option><option value="July">July</option><option value="January">January</option><option value="February">February</option><option value="April">April</option><option value="August">August</option><option value="November">November</option></select>

How can I sort it by month name so that it comes in dropdown like Jan, Feb and so on..

Below is the piece of code used

JSONArray jsonArray = new JSONArray(rowfielddata.getString("option_values"));
                    for (int i = 0; i < jsonArray.length(); i++) {
                        JSONObject json = jsonArray.getJSONObject(i);
                        Iterator<String> keys = json.keys();
                        while (keys.hasNext()) {
                            String key = keys.next();
                            f2 = f2 + "<option value='" + key + "'>" + json.get(key) + "</option>";
                        }

                    }

Thanks in advance!!

Answer 1

Perhaps you can change the part that iterates over the keys by the following solution:

If you have a single object with the months as keys you may need an aditional array that maps the month as a number to the key of the single object.

String []  monthsMapping = new String[12];
monthsMapping[0] = "January";
...
monthsMapping[11] = "December";

Then you genereate the options looping through this array:

for(int i=0; i<12; i++){
   //Generate the 12 options
   ... +  singleMonthJSONObject.getString(monthsMapping[i]) + ...;
}

Answer 2

To me your input json looks to be incorrect, if you can modify the JSON to below structure:

    [{"monthName": "January","order":1},
      {"monthName": "February","order":2},
       {"monthName": "March","order":3},
        {"monthName": "April","order":4},
        {"monthName": "May","order":5},
        {"monthName": "June","order":6},
        {"monthName": "July","order":7},
        {"monthName": "August","order":8},
        {"monthName": "September","order":9},
        {"monthName": "October","order":10},
        {"monthName": "November","order":11},
        {"monthName": "December","order":12}]

Above JSON will give you array Now next you need to do after reading data in JSONArray sort the data based on order value

JSONArray jsonArray = jsonResult.getJSONArray("getalldata");

JSONArray sortedJsonArray = new JSONArray();
    List<JSONObject> jsonValues = new ArrayList<JSONObject>();
    for (int i = 0; i < jsonArr.length(); i++) {
        jsonValues.add(jsonArr.getJSONObject(i));
    }
    Collections.sort( jsonValues, new Comparator<JSONObject>() {

        private static final String KEY_NAME = "order";

        @Override
        public int compare(JSONObject a, JSONObject b) {
            String valA = new String();
            String valB = new String();

            try {
                valA = (String) a.get(KEY_NAME);
                valB = (String) b.get(KEY_NAME);
            } 
            catch (JSONException e) {
                //do something
            }
            return valA.compareTo(valB);
           }
    });

    for (int i = 0; i < jsonValues.length(); i++) {
        JSONObject jsonObj= jsonValues.getJSONObject(i);
                             f2 = f2 + "<option value='" + 
      jsonObj.optString("id")+ "'>" + jsonObj.optString("monthName") + "
      </option>";
    }

I assume there is another attribute also in the json with name id as this is being used to assign value in option tag