/**     * 返回随机List     * @param list 备选     * @param selected 备选数量     * @return     */    public  List getRandomNum(List list, int selected) {        List<Object> reList = new ArrayList<Object>();        Random random = new Random();        // 先抽取，备选数量的个数        if (list.size() >= selected) {            for (int i = 0; i < selected; i++) {                // 随机数的范围为0-list.size()-1;                int target = random.nextInt(list.size());                reList.add(list.get(target));                list.remove(target);            }        } else {            selected = list.size();            for (int i = 0; i < selected; i++) {                // 随机数的范围为0-list.size()-1;                int target = random.nextInt(list.size());                reList.add(list.get(target));                list.remove(target);            }        }              return reList;    }