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PHP实现雪花算法生成唯一ID

news 2025/6/28 5:39:31

引言

雪花算法是Twitter开源的分布式ID生成算法，可以产生64位的ID。其中第一位是固定的正数标识，41位用于存储时间戳，剩下的为机器ID和序列号。通过时间戳、机器ID和序列号的组合，确保每个ID都是唯一的。

PHP代码

1、定义雪花算法类

class Snowflake
{private int $datacenterId; // 数据中心IDprivate int $machineId;    // 机器IDprivate int $sequence = 0; // 序列号private int $lastTimestamp = -1; // 上一个时间戳private const DATA_CENTER_ID_BITS = 5; // 数据中心ID所占位数private const MACHINE_ID_BITS = 5;      // 机器ID所占位数private const SEQUENCE_BITS = 12;        // 序列号所占位数private const MAX_DATA_CENTER_ID = -1 ^ (-1 << self::DATA_CENTER_ID_BITS);private const MAX_MACHINE_ID = -1 ^ (-1 << self::MACHINE_ID_BITS);private const TIMESTAMP_LEFT_SHIFT = self::SEQUENCE_BITS + self::MACHINE_ID_BITS + self::DATA_CENTER_ID_BITS;private const SEQUENCE_LEFT_SHIFT = self::MACHINE_ID_BITS + self::DATA_CENTER_ID_BITS;private int $epoch; // 起始时间戳public function __construct(int $datacenterId, int $machineId){if ($datacenterId < 0 || $datacenterId > self::MAX_DATA_CENTER_ID) {throw new Exception("数据中心ID超出范围");}if ($machineId < 0 || $machineId > self::MAX_MACHINE_ID) {throw new Exception("机器ID超出范围");}$this->datacenterId = $datacenterId;$this->machineId = $machineId;$this->epoch = 1609430400000; // 自定义起始时间（例如2021年1月1日）}public function nextId(): int{$timestamp = $this->currentTimeMillis();if ($timestamp < $this->lastTimestamp) {throw new Exception("错误：系统时钟发生回拨");}if ($this->lastTimestamp === $timestamp) {$this->sequence = ($this->sequence + 1) & ((1 << self::SEQUENCE_BITS) - 1);if ($this->sequence === 0) {$timestamp = $this->waitNextMillis($timestamp);}} else {$this->sequence = 0;}$this->lastTimestamp = $timestamp;return (($timestamp - $this->epoch) << self::TIMESTAMP_LEFT_SHIFT) |($this->datacenterId << self::SEQUENCE_LEFT_SHIFT) |($this->machineId << self::SEQUENCE_BITS) |$this->sequence;}private function waitNextMillis(int $lastTimestamp): int{$timestamp = $this->currentTimeMillis();while ($timestamp <= $lastTimestamp) {$timestamp = $this->currentTimeMillis();}return $timestamp;}private function currentTimeMillis(): int{return (int)(microtime(true) * 1000);}
}

2、创建实例生成ID

// 创建雪花算法实例
$datacenterId = 1; // 数据中心ID
$machineId = 1;    // 机器ID
$snowflake = new Snowflake($datacenterId, $machineId);// 生成用户ID的示例
for ($i = 0; $i < 10; $i++) {$userId = $snowflake->nextId();echo "生成的用户ID: $userId"."<br/>";
}

3、查看生成结果

生成的用户ID: 507485100926047232
生成的用户ID: 507485100926047233
生成的用户ID: 507485100926047234
生成的用户ID: 507485100926047235
生成的用户ID: 507485100926047236
生成的用户ID: 507485100926047237
生成的用户ID: 507485100926047238
生成的用户ID: 507485100926047239
生成的用户ID: 507485100926047240
生成的用户ID: 507485100926047241