simple-json List<Map> 을 json으로 직렬화

public String getList(RequestSet requestSet){
		List<Map<String, String>> list = sqlSession.selectList("getList", requestSet);
		return getJsonStringFromListMap(list);
	}
	
	//utils
	@SuppressWarnings("unchecked")
	public static String getJsonStringFromListMap( List<Map<String, String>> list ) {
	    JSONArray jsonArray = new JSONArray();
	    for( Map<String, String> map : list ) {
	        jsonArray.add( getJsonStringFromMap( map ) );
	    }
	    return jsonArray.toJSONString();
	}
	
	//utils
	@SuppressWarnings("unchecked")
	public static JSONObject getJsonStringFromMap( Map<String, String> map ) {
		JSONObject jsonObj = new JSONObject();
		for( Map.Entry<String, String> entry : map.entrySet() ) {
			String key = entry.getKey();
            Object value = entry.getValue();
            jsonObj.put(key, value);
        }
        return jsonObj;
	}