Hutool工具类RandomUtil实现抽奖核心逻辑

一、从奖品列表中按奖品中奖概率选中一个作为中奖奖品

private LuckyAward draw(Long activityId) {
        //获取抽奖奖品列表
        List<LuckyAward> luckyAwards = luckyAwardService.listLuckyAward(activityId);

        if (null == luckyAwards || luckyAwards.size() == 0) {
            throw new Exception("奖品发完");
        }

        List<WeightRandom.WeightObj<LuckyAward>> weightObjs = new ArrayList<>();

        //安慰奖，不限量
        LuckyAward defaultAward = null;
        Optional<LuckyAward> defaultAwardOpt = luckyAwards.stream().filter(f -> f.getComfort()).findFirst();
        if (defaultAwardOpt.isPresent()) {
            defaultAward = defaultAwardOpt.get();
        }

        luckyAwards.forEach(award -> {
            weightObjs.add(new WeightRandom.WeightObj<>(award, award.getProbability()));
        });

        if (weightObjs.size() == 0) {
            throw new Exception("奖品发完");
        }

        //从奖品列表中按奖品中奖概率选中一个作为中奖奖品
        WeightRandom random = RandomUtil.weightRandom(weightObjs);
        LuckyAward award = (LuckyAward) random.next();

        if (null != awardStockRdsHelper.popAward(award.getId())) {
            return award;
        } else {
            if (null == defaultAward) {
                throw new Exception("奖品发完");
            }
            return defaultAward;
        }
    }

奖品对象

public class LuckyAward extends BaseModel<LuckyAward> {

    /**
     * 抽奖活动ID
     */
    private Long activityId;

    /**
     * 奖品编号
     */
    private String awardNo;

    /**
     * 奖品等级
     */
    private String awardGrade;

    /**
     * 奖品类型
     */
    private AwardTypeEnum awardType;

    /**
     * 奖品名称
     */
    private String awardName;

    /**
     * 图片地址
     */
    private String imageUrl;

    /**
     * 奖品价值
     */
    private String worth;

    /**
     * 奖品数量
     */
    private Integer awardNumber;

    /**
     * 已发放数
     */
    private Integer grandNumber;

    /**
     * 中奖概率
     */
    private Double probability;

    /**
     * 排序序号
     */
    private Integer orderNumber;

    /**
     * 是否为安慰奖
     */
    private Boolean comfort;
}