分布式 id 生成器

public class SnowflakeIdWorker {
 // ==============================Fields==================
    /** 开始时间截 (2019-08-06) */
    private final long twepoch = 1565020800000L;

    /** 机器id所占的位数 */




    

    private final long workerIdBits = 5L;

    /** 数据标识id所占的位数 */
    private final long datacenterIdBits = 5L;

    /** 支持的最大机器id，结果是31 (这个移位算法可以很快的计算出几位二进制数所能表示的最大十进制数) */
    private final long maxWorkerId = -1L ^ (-1L << workerIdBits);

    /** 支持的最大数据标识id，结果是31 */
    private final long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);

    /** 序列在id中占的位数 */
    private final long sequenceBits = 12L;

    /** 机器ID向左移12位 */
    private final long workerIdShift = sequenceBits;

    /** 数据标识id向左移17位(12+5) */
    private final long datacenterIdShift = sequenceBits + workerIdBits;

    /** 时间截向左移22位(5+5+12) */
    private final long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;

    /** 生成序列的掩码，这里为4095 (0b111111111111=0xfff=4095) */
    private final long sequenceMask = -1L ^ (-1L << sequenceBits);

    /** 工作机器ID(0~31) */
    private long workerId;

    /** 数据中心ID(0~31) */
    private long datacenterId;

    /** 毫秒内序列(0~4095) */
    private long sequence = 0L;

    /** 上次生成ID的时间截 */
    private long lastTimestamp = -1L;

     //==============================Constructors====================
    /**
     * 构造函数
     * @param workerId 工作ID (0~31)
     * @param datacenterId 数据中心ID (0~31)
     */
    public SnowflakeIdWorker(long workerId, long datacenterId) {
        if (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;
    }

    // ==============================Methods=================================
    /**
     * 获得下一个ID (该方法是线程安全的)
     * @return SnowflakeId
     */
    public




    
 synchronized long nextId() {
        long timestamp = timeGen();

        //如果当前时间小于上一次ID生成的时间戳，说明系统时钟回退过这个时候应当抛出异常
        if (timestamp < lastTimestamp) {
            throw new RuntimeException(
                    String.format("Clock moved backwards. Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));
        }

        //如果是同一时间生成的，则进行毫秒内序列
        if (lastTimestamp == timestamp) {
            sequence = (sequence + 1) & sequenceMask;
            //毫秒内序列溢出
            if (sequence == 0) {
                //阻塞到下一个毫秒,获得新的时间戳
                timestamp = tilNextMillis(lastTimestamp);
            }
        }
        //时间戳改变，毫秒内序列重置
        else {
            sequence = 0L;
        }

        //上次生成ID的时间截
        lastTimestamp = timestamp;

        //移位并通过或运算拼到一起组成64位的ID
        return ((timestamp - twepoch) << timestampLeftShift) //
                | (datacenterId << datacenterIdShift) //
                | (workerId << workerIdShift) //
                | sequence;
    }

    /**
     * 阻塞到下一个毫秒，直到获得新的时间戳
     * @param lastTimestamp 上次生成ID的时间截
     * @return 当前时间戳
     */
    protected long tilNextMillis(long lastTimestamp) {
        long timestamp = timeGen();
        while (timestamp <= lastTimestamp) {
            timestamp = timeGen();
        }
        return timestamp;
    }

    /**
     * 返回以毫秒为单位的当前时间
     * @return 当前时间(毫秒)
     */
    protected long timeGen() {
        return System.currentTimeMillis();
    }

    //==============================Test=============================================
    /** 测试 */
    public static void main(String[] args) {
        SnowflakeIdWorker idWorker = new SnowflakeIdWorker(0, 0);
        for (int i = 0; i < 1000; i++) {
            long id = idWorker.nextId();
            System.out.println(Long.toBinaryString(id));
            System.out.println(id);
        }
    }
}

<dependency>
    <groupId




    
>cn.hutoolgroupId>
    <artifactId>hutool-captchaartifactId>
    <version>${hutool.version}version>
dependency>

public class IdGenerator {

    private long workerId = 0;

    @PostConstruct
    void init() {
        try {
            workerId = NetUtil.ipv4ToLong(NetUtil.getLocalhostStr());
            log.info("当前机器 workerId: {}", workerId);
        } catch (Exception e) {
            log.warn("获取机器 ID 失败", e);
            workerId = NetUtil.getLocalhost().hashCode();
            log.info("当前机器 workerId: {}", workerId);
        }
    }

    /**
     * 获取一个批次号，形如 2019071015301361000101237
     *

     * 数据库使用 char(25) 存储
     *
     * @param tenantId 租户ID，5 位
     * @param module 业务模块ID，2 位
     * @return 返回批次号
     */
    public synchronized String batchId(int tenantId, int module) {
        String prefix = DateTime.now().toString(DatePattern.PURE_DATETIME_MS_PATTERN);
        return prefix + tenantId + module + RandomUtil.randomNumbers(3);
    }

    @Deprecated
    public synchronized String getBatchId(int tenantId, int module) {
        return batchId(tenantId, module);
    }

    /**
     * 生成的是不带-的字符串，类似于：b17f24ff026d40949c85a24f4f375d42
     *
     * @return
     */
    public String simpleUUID() {
        return IdUtil.simpleUUID();
    }

    /**
     * 生成的UUID是带-的字符串，类似于：a5c8a5e8-df2b-4706-bea4-08d0939410e3
     *
     * @return
     */
    public String randomUUID() {
        return IdUtil.randomUUID();
    }

    private Snowflake snowflake = IdUtil.createSnowflake(workerId, 1);

    public synchronized long snowflakeId() {
        return snowflake.nextId();
    }

    public synchronized long snowflakeId(long workerId, long