public class IdWorker {
// 時間起始標(biāo)記點(diǎn)，作為基準(zhǔn)，一般取系統(tǒng)的最近時間（一旦確定不能變動）
private final static long twepoch = 1288834974657L;
// 機(jī)器標(biāo)識位數(shù)
private final static long workerIdBits = 5L;
// 數(shù)據(jù)中心標(biāo)識位數(shù)
private final static long datacenterIdBits = 5L;
// 機(jī)器ID最大值
private final static long maxWorkerId = -1L ^ (-1L << workerIdBits);
// 數(shù)據(jù)中心ID最大值
private final static long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
// 毫秒內(nèi)自增位
private final static long sequenceBits = 12L;
// 機(jī)器ID偏左移12位
private final static long workerIdShift = sequenceBits;
// 數(shù)據(jù)中心ID左移17位
private final static long datacenterIdShift = sequenceBits + workerIdBits;
// 時間毫秒左移22位
private final static long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;

private final static long sequenceMask = -1L ^ (-1L << sequenceBits);
/* 上次生產(chǎn)id時間戳 */
private static long lastTimestamp = -1L;
// 0温艇，并發(fā)控制
private long sequence = 0L;

private final long workerId;
// 數(shù)據(jù)標(biāo)識id部分
private final long datacenterId;

public IdWorker(){
    this.datacenterId = getDatacenterId(maxDatacenterId);
    this.workerId = getMaxWorkerId(datacenterId, maxWorkerId);
}
/**
 * @param workerId
 *            工作機(jī)器ID
 * @param datacenterId
 *            序列號
 */
public IdWorker(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;
}
/**
 * 獲取下一個ID
 *
 * @return
 */
public synchronized long nextId() {
    long timestamp = timeGen();
    if (timestamp < lastTimestamp) {
        throw new RuntimeException(String.format("Clock moved backwards.  Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));
    }

    if (lastTimestamp == timestamp) {
        // 當(dāng)前毫秒內(nèi)竖伯，則+1
        sequence = (sequence + 1) & sequenceMask;
        if (sequence == 0) {
            // 當(dāng)前毫秒內(nèi)計數(shù)滿了沟娱，則等待下一秒
            timestamp = tilNextMillis(lastTimestamp);
        }
    } else {
        sequence = 0L;
    }
    lastTimestamp = timestamp;
    // ID偏移組合生成最終的ID铭污，并返回ID
    long nextId = ((timestamp - twepoch) << timestampLeftShift)
            | (datacenterId << datacenterIdShift)
            | (workerId << workerIdShift) | sequence;

    return nextId;
}

private long tilNextMillis(final long lastTimestamp) {
    long timestamp = this.timeGen();
    while (timestamp <= lastTimestamp) {
        timestamp = this.timeGen();
    }
    return timestamp;
}

private long timeGen() {
    return System.currentTimeMillis();
}

/**
 * <p>
 * 獲取 maxWorkerId
 * </p>
 */
protected static long getMaxWorkerId(long datacenterId, long maxWorkerId) {
    StringBuffer mpid = new StringBuffer();
    mpid.append(datacenterId);
    String name = ManagementFactory.getRuntimeMXBean().getName();
    if (!name.isEmpty()) {
        /*
         * GET jvmPid
         */
        mpid.append(name.split("@")[0]);
    }
    /*
     * MAC + PID 的 hashcode 獲取16個低位
     */
    return (mpid.toString().hashCode() & 0xffff) % (maxWorkerId + 1);
}

/**
 * <p>
 * 數(shù)據(jù)標(biāo)識id部分
 * </p>
 */
protected static long getDatacenterId(long maxDatacenterId) {
    long id = 0L;
    try {
        InetAddress ip = InetAddress.getLocalHost();
        NetworkInterface network = NetworkInterface.getByInetAddress(ip);
        if (network == null) {
            id = 1L;
        } else {
            byte[] mac = network.getHardwareAddress();
            id = ((0x000000FF & (long) mac[mac.length - 1])
                    | (0x0000FF00 & (((long) mac[mac.length - 2]) << 8))) >> 6;
            id = id % (maxDatacenterId + 1);
        }
    } catch (Exception e) {
        System.out.println(" getDatacenterId: " + e.getMessage());
    }
    return id;
}


public static void main(String[] args) {
    IdWorker idWorker = new IdWorker();
    long nextId = idWorker.nextId();
        System.out.println(nextId);



}

}