java 雪花算法改造（带日期格式）毫秒级

雪花算法实现：生成唯一ID的SnowFlake序列

最新推荐文章于 2023-12-20 19:12:46 发布

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最新推荐文章于 2023-12-20 19:12:46 发布 · 848 阅读

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#java #算法

本文介绍了一个使用Java实现的SnowFlake算法，用于生成全局唯一的ID，包括序列生成、时间戳处理和序列溢出处理。通过实例展示了ID的生成过程。

import java.util.Date;

public class MySnowFlake {
    private long lastTimestamp = -1L;
    private int sequence;
    private final int sequenceMask=999;
    public MySnowFlake(Integer sequence){
        if (sequence<0||sequence>sequenceMask){
            throw new IllegalArgumentException(
                    "sequence can't be greater than 999 or lesser than 0"
            );
        }
        this.sequence=sequence;

    }
    public synchronized String nextId() {
        String result="";
        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));
        }
        if (lastTimestamp == timestam