/**
     * 将一组数据固定分组，每组n个元素
     *
     * @param source 要分组的数据源
     * @param limit      每组n个元素
     * @param <T>
     * @return
     */
    public static <T> List<List<T>> fixedGroup(List<T> source, int limit) {
        if (null == source || source.size() == 0 || limit <= 0)
            return null;
        List<List<T>> result = new ArrayList<List<T>>();
        int remainder = source.size() % limit;
        int size = (source.size() / limit);
        for (int i = 0; i < size; i++) {
            List<T> subset = null;
            subset = source.subList(i * limit, (i + 1) * limit);
            result.add(subset);
        }
        if (remainder > 0) {
            List<T> subset = null;
            subset = source.subList(size * limit, size * limit + remainder);
            result.add(subset);
        }
        return result;
    }