PHP实现普通hash分布式算法简单示例

<?php/* * 普通hash分布式算法 * @param $key * @return int */class Hash{  protected $_serverList = array();  public function __construct($_serverList){    if(is_array($_serverList)){      $this->_serverList = $_serverList;    }else{      return false;    }  }  //通过hash算法返回一个整数值  protected function myHash($key){    $md5 = substr(md5($key),0,8);    $seed = 31; //种子值    $hash=0;    for($i=0;$i<8;$i++){      $hash = $hash*$seed+ord($md5{$i}); //ord 返回ascii值      $i++;    }    return $hash&0x7FFFFFFF; //0x7FFFFFFF表示最大值  }  public function getServer($key){    $servers = $this->_serverList;    $rs = $servers[$this->myHash($key)%(count($servers))];    return $rs;  }}$servers = array(  array('host'=>'192.168.1.1','port'=>6397),  array('host'=>'192.168.1.2','port'=>6397),  array('host'=>'192.168.1.3','port'=>6397),  array('host'=>'192.168.1.4','port'=>6397),  array('host'=>'192.168.1.5','port'=>6397),  array('host'=>'192.168.1.6','port'=>6397),  array('host'=>'192.168.1.7','port'=>6397),);$key = 'TheKey'.rand(0,99999);$value = 'TheValue';$hash = new Hash($servers);if($hash){  $server = $hash->getServer($key);  // $memcached = new Memcached($sc);  // $memcached->set($key,$value);}?>