随机列表

import cn.hutool.core.util.RandomUtil;
    public List<Long> getRandomIds(List<Long> mchIds) {
        // 随机之前
        List<Long> beforeList = Arrays.asList(1L,2L,3L,4L);
        // 随机之后
        List<Long> randomList = new ArrayList<>();
        while (beforeList.size() > 0) {
            int randomNum = RandomUtil.randomInt(beforeList.size());
            randomList.add(beforeList.get(randomNum));
            beforeList.remove(randomNum);
        }
        return randomList;
    }