雪花算法 代码

/*** @author lwh* @date 2023/9/5* @description 批量插入，手动设置**/
public class IdWorker {//因为二进制里第一个 bit 为如果是 1，那么都是负数，但是我们生成的 id 都是正数，所以第一个 bit 统一都是 0。//机器ID  2进制5位  32位减掉1位 31个private long workerId;//机房ID 2进制5位  32位减掉1位 31个private long datacenterId;//代表一毫秒内生成的多个id的最新序号  12位 4096 -1 = 4095 个private long sequence;//设置一个时间初始值    2^41 - 1   差不多可以用69年private long twepoch = 1585644268888L;//5位的机器idprivate long workerIdBits = 5L;//5位的机房idprivate long datacenterIdBits = 5L;//每毫秒内产生的id数 2 的 12次方private long sequenceBits = 12L;// 这个是二进制运算，就是5 bit最多只能有31个数字，也就是说机器id最多只能是32以内private long maxWorkerId = -1L ^ (-1L << workerIdBits);// 这个是一个意思，就是5 bit最多只能有31个数字，机房id最多只能是32以内private long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);private long workerIdShift = sequenceBits;private long datacenterIdShift = sequenceBits + workerIdBits;private long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;private long sequenceMask = -1L ^ (-1L << sequenceBits);//记录产生时间毫秒数，判断是否是同1毫秒private long lastTimestamp = -1L;public long getWorkerId(){return workerId;}public long getDatacenterId() {return datacenterId;}public long getTimestamp() {return System.currentTimeMillis();}public IdWorker(long workerId, long datacenterId, long sequence) {// 检查机房id和机器id是否超过31 不能小于0if (workerId > maxWorkerId || workerId < 0) {throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0",maxWorkerId));}if (datacenterId > maxDatacenterId || datacenterId < 0) {throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0",maxDatacenterId));}this.workerId = workerId;this.datacenterId = datacenterId;this.sequence = sequence;}// 这个是核心方法，通过调用nextId()方法，让当前这台机器上的snowflake算法程序生成一个全局唯一的idpublic synchronized long nextId() {// 这儿就是获取当前时间戳，单位是毫秒long timestamp = timeGen();if (timestamp < lastTimestamp) {System.err.printf("clock is moving backwards. Rejecting requests until %d.", lastTimestamp);throw new RuntimeException(String.format("Clock moved backwards. Refusing to generate id for %d milliseconds",lastTimestamp - timestamp));}// 下面是说假设在同一个毫秒内，又发送了一个请求生成一个id// 这个时候就得把seqence序号给递增1，最多就是4096if (lastTimestamp == timestamp) {// 这个意思是说一个毫秒内最多只能有4096个数字，无论你传递多少进来，//这个位运算保证始终就是在4096这个范围内，避免你自己传递个sequence超过了4096这个范围sequence = (sequence + 1) & sequenceMask;//当某一毫秒的时间，产生的id数 超过4095，系统会进入等待，直到下一毫秒，系统继续产生IDif (sequence == 0) {timestamp = tilNextMillis(lastTimestamp);}} else {sequence = 0;}// 这儿记录一下最近一次生成id的时间戳，单位是毫秒lastTimestamp = timestamp;// 这儿就是最核心的二进制位运算操作，生成一个64bit的id// 先将当前时间戳左移，放到41 bit那儿；将机房id左移放到5 bit那儿；将机器id左移放到5 bit那儿；将序号放最后12 bit// 最后拼接起来成一个64 bit的二进制数字，转换成10进制就是个long型return ((timestamp - twepoch) << timestampLeftShift) |(datacenterId << datacenterIdShift) |(workerId << workerIdShift) | sequence;}/*** 当某一毫秒的时间，产生的id数 超过4095，系统会进入等待，直到下一毫秒，系统继续产生ID* @param lastTimestamp* @return*/private long tilNextMillis(long lastTimestamp) {long timestamp = timeGen();while (timestamp <= lastTimestamp) {timestamp = timeGen();}return timestamp;}//获取当前时间戳private long timeGen(){return System.currentTimeMillis();}/***  main 测试类* @param args*/public static void main(String[] args) {IdWorker worker = new IdWorker(1,1,1);for (int i = 0; i < 22; i++) {System.out.println(worker.nextId());}}
}

/*** @author lwh* @date 2023/9/5* @description**/
@Configuration
@Slf4j
public class SnowFlakeIdConfig {/*** @author lwh* @date 2023/9/5* @description 创建分布式ID对象**/@Beanpublic IdWorker idWorker() {Env env = ApolloInjector.getInstance(ConfigUtil.class).getApolloEnv();IdWorker idWorker = new IdWorker(getWorkId(), getDataCenterId(), 10);String msg = StrFormatter.format("【{}】IdWorker创建完成。WordId:{}，DataCenterId:{}", env.name(), idWorker.getWorkerId(), idWorker.getDatacenterId());log.warn(msg);return idWorker;}/*** workId使用IP生成* @return workId*/private static Long getWorkId() {try {String hostAddress = Inet4Address.getLocalHost().getHostAddress();int[] ints = StringUtils.toCodePoints(hostAddress);int sums = 0;for (int b : ints) {sums = sums + b;}return (long) (sums % 32);}catch (UnknownHostException e) {// 失败就随机return RandomUtils.nextLong(0, 31);}}/*** dataCenterId使用hostName生成* @return dataCenterId*/private static Long getDataCenterId() {try {String hostName = SystemUtils.getHostName();int[] ints = StringUtils.toCodePoints(hostName);int sums = 0;for (int i: ints) {sums = sums + i;}return (long) (sums % 32);}catch (Exception e) {// 失败就随机return RandomUtils.nextLong(0, 31);}}
}

使用：

  	@Autowiredprivate IdWorker idWorker;// 根据订单保存任务量scanTaskNumberList.stream().forEach(k -> k.setId(idWorker.nextId()));scanTaskNumberService.saveBatch(scanTaskNumberList);

集群部署下，动态生成雪花算法WorkId和DataCenterId_雪花 workerid-CSDN博客 

snowflake算法的workerId问题-腾讯云开发者社区-腾讯云