java servlet 按月份名称对 json 数据进行排序

Question

我有一个 json 数组，其中包含单个对象，键为月份名称。当来自 Db 时，它看起来像 [{ "January": "January", "February": "February", "March": "March", "April": "April", "May": "May", "June": "June", "July": "July", "August": "August", "September": "September", "October": "October", "November": "November", "December": "December" }] 在前端它看起来像

<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>

如何按月份名称对其进行排序，以便它出现在 Jan、Feb 等下拉列表中。

下面是使用的一段代码

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>";
                        }

                    }

提前致谢！！

Answer 1

也许您可以通过以下解决方案更改遍历键的部分：

如果您有一个以月份为键的对象，您可能需要一个附加数组，将月份作为数字映射到单个对象的键。

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

然后你生成遍历这个数组的选项：

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

Answer 2

如果您可以将 JSON 修改为以下结构，对我来说您的输入 json 看起来不正确：

    [{"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}]

上面的 JSON 会给你数组 现在接下来您需要在 JSONArray 中读取数据后根据订单值对数据进行排序

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>";
    }

我假设 json 中还有另一个名为 id 的属性，因为它用于在选项标签中分配值