map排序，map轉json防止順序錯亂

public static void main(String[] args) {
		 Map<String, String> mapsort = new TreeMap<String, String>(
	                new Comparator<String>() {
	                    public int compare(String obj1, String obj2) {
	                        // 降序排序
	                        return obj2.compareTo(obj1);
	                    }
	                });
		 Map<String,String> map = new HashMap<String, String>();
		 map.put("2018-04", "123");
		 map.put("2018-01", "123");
		 map.put("2018-05", "123");
		 map.put("2018-02", "123");
		 map.put("2018-06", "123");
		 mapsort.putAll(map);
		 for (String key : mapsort.keySet()) { 
			  System.out.println("Key = " + key); 
			} 
	}

 //防止順序錯亂

mapsort=JSON.parseObject(mapsort.toString(),new TypeReference<TreeMap<String, String>>(){} ,Feature.OrderedField);