JAVA 雪花演算法

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package util;/** * 雪花演算法 * * @author zengwei * @email [email protected] * @date 2018-03-25 22:02 */public class IdWorker {    private final long workerId;    private final long snsEpoch = 1330328109047L;    private long sequence = 0L;    private final long workerIdBits = 10L;    private final long maxWorkerId = -1L ^ -1L << this.workerIdBits;    private final long sequenceBits = 12L;    private final long workerIdShift = this.sequenceBits;    private final long timestampLeftShift = this.sequenceBits + this.workerIdBits;    private final long sequenceMask = -1L ^ -1L << this.sequenceBits;    private long lastTimestamp = -1L;    public IdWorker(long workerId) {        super();        if (workerId > this.maxWorkerId || workerId < 0) {            throw new IllegalArgumentException(String.format("worker Id can‘t be greater than %d or less than 0", this.maxWorkerId));        }        this.workerId = workerId;    }    public synchronized long nextId() throws Exception {        long timestamp = this.timeGen();        if (this.lastTimestamp == timestamp) {            this.sequence = this.sequence + 1 & this.sequenceMask;            if (this.sequence == 0) {                timestamp = this.tilNextMillis(this.lastTimestamp);            }        } else {            this.sequence = 0;        }        if (timestamp < this.lastTimestamp) {            throw new Exception(String.format("Clock moved backwards.Refusing to generate id for %d milliseconds", (this.lastTimestamp - timestamp)));        }        this.lastTimestamp = timestamp;        return timestamp - this.snsEpoch << this.timestampLeftShift | this.workerId << this.workerIdShift | this.sequence;    }    /**     * 保證返回的毫秒數在參數之後     *      * @param lastTimestamp     * @return     */    private long tilNextMillis(long lastTimestamp) {        long timestamp = this.timeGen();        while (timestamp <= lastTimestamp) {            timestamp = this.timeGen();        }        return timestamp;    }    /**     * 獲得系統當前毫秒數     *      * @return     */    private long timeGen() {        return System.currentTimeMillis();    }        public static void main(String[] args) {        Integer workId = 1;        IdWorker idWork = new IdWorker(workId);        try {            System.out.println(String.valueOf(idWork.nextId()));        } catch (Exception e) {            e.printStackTrace();        }    }}

　　

JAVA 雪花演算法