负载均衡加权轮询算法

随机数加权轮询算法

public int select() {
        int[] weights = {10, 20, 50};
        int totalWeight = weights[0] + weights[1] + weights[2];
        // 取随机数
        int offset = ThreadLocalRandom.current().nextInt(totalWeight);
        for (int i = 0; i < weights.length; i++) {
            offset -= weights[i];
            if (offset < 0) {
                return i;
            }
        }
        return -1;
    }

平滑加权轮询算法

int[] weights = {10, 20, 50};   // 节点权重
    int totalWeight = weights[0] + weights[1] + weights[2]; // 总权重
    int[] current = new int[]{10, 20, 50};  // 初始化当前权重

    public int select() {
        int maxCurrent = -1, selected = -1;
        // 遍历所有节点，找到当前权重最大的节点
        for (int i = 0; i < weights.length; i++) {
            // 重新计算当前权重
            current[i] += weights[i];
            int cur = current[i];
            if (cur > maxCurrent) {
                maxCurrent = cur;
                selected = i;
            }
        }
        // 被选中的节点减去总权重
        current[selected] -= totalWeight;
        return selected;
    }