ZooKeeper源码阅读——客户端负载均衡算法

  zk客户端连接、ping server端时采用了轮询算法作为负载均衡算法。每次向服务端发送ping请求时，都会调用next方法获取一个server地址，然后发送ping请求。

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public InetSocketAddress next(long spinDelay) {
    ++currentIndex;
    if (currentIndex == serverAddresses.size()) {
        currentIndex = 0;
    }
    if (currentIndex == lastIndex && spinDelay > 0) {
        try {
            Thread.sleep(spinDelay);
        } catch (InterruptedException e) {
            LOG.warn("Unexpected exception", e);
        }
    } else if (lastIndex == -1) {
        // We don't want to sleep on the first ever connect attempt.
        lastIndex = 0;
    }

    return serverAddresses.get(currentIndex);
}