这篇文章主要介绍了round robin权重轮循算法php实现代码,需要的朋友可以参考下

先上代码，采用php脚本语言

/*

* Copyright (C) FatHong

*/

/* 数据初始化，weight: 权重 */

$hosts['a'] = array('weight' => 5, 'current_weight' => 0, 'count' => 0);

$hosts['b'] = array('weight' => 3, 'current_weight' => 0, 'count' => 0);

$hosts['c'] = array('weight' => 2, 'current_weight' => 0, 'count' => 0);

$result = array();

/* 模拟10次 */

for ($i = 0; $i < 10; $i++) {

round_robin($hosts, $result);

}

/* 输出结果 */

print_r($result);

/* round robin 轮循 */

function round_robin(&$hosts, &$result)

{

$total = 0;

$best = null;

foreach ($hosts as $key => $item) {

$current = &$hosts[$key];

$weight = $current['weight'];

$current['current_weight'] += $weight;

$total += $weight;

if ( ($best == null) || ($hosts[$best]['current_weight'] <

$current['current_weight']) )

{

$best = $key;

}

}

$hosts[$best]['current_weight'] -= $total;

$hosts[$best]['count']++;

$result[] = $best;

}

输出结果：

Array

(

[0] => a

[1] => b

[2] => c

[3] => a

[4] => a

[5] => b

[6] => a

[7] => c

[8] => b

[9] => a

)

负载均衡的服务器中，其实现算法有种是round-robin权重轮循，就是后端的服务器列表中，给每个服务器标上权重，代表它被采用的机率。

这段代码把最简洁的流程剥离出来，没考虑后端挂起等情况，可以知道它是怎么实现的，仅供参考.