Java抽奖

 随便写一个抽奖的小Demo  drawList是奖品集合，里面有奖品中间的概率

    
    private int randomDrawListIndex(List drawList) {
        int random = -1;
        // 总权重
        int sumWeight = 10000;
        double randomNumber = new SecureRandom().nextDouble() * sumWeight;
        // 根据随机数在所有奖品分布的区域并确定所抽奖品
        int d1 = 0;
        int d2 = 0;
        for (int i = 0; i < drawList.size(); i++) {
            if (i == 0) {
                d1 = 1;
            } else {
                d1 += drawList.get(i - 1).getProbNum();
            }

            d2 += drawList.get(i).getProbNum();

            if (d1 <= randomNumber && randomNumber <= d2) {
                random = i;
                break;
            }
        }

        return random;
    }