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@@ -0,0 +1,78 @@
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+package com.zhentao.utils;
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+
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+/**
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+ * @Date 2025/4/21 19:25
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+ * @Author gln
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+ **/
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+
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+public class SnowflakeUtil {
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+ // 起始时间戳,可自定义,这里以 2020-01-01 00:00:00 为例
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+ private static final long START_TIMESTAMP = 1577836800000L;
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+
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+ // 数据中心 ID 所占位数
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+ private static final long DATA_CENTER_ID_BITS = 5L;
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+ // 机器 ID 所占位数
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+ private static final long WORKER_ID_BITS = 5L;
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+ // 序列号所占位数
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+ private static final long SEQUENCE_BITS = 12L;
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+
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+ // 数据中心 ID 最大值
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+ private static final long MAX_DATA_CENTER_ID = -1L ^ (-1L << DATA_CENTER_ID_BITS);
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+ // 机器 ID 最大值
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+ private static final long MAX_WORKER_ID = -1L ^ (-1L << WORKER_ID_BITS);
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+ // 序列号最大值
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+ private static final long SEQUENCE_MASK = -1L ^ (-1L << SEQUENCE_BITS);
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+
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+ // 机器 ID 向左移位数
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+ private static final long WORKER_ID_SHIFT = SEQUENCE_BITS;
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+ // 数据中心 ID 向左移位数
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+ private static final long DATA_CENTER_ID_SHIFT = SEQUENCE_BITS + WORKER_ID_BITS;
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+ // 时间戳向左移位数
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+ private static final long TIMESTAMP_LEFT_SHIFT = SEQUENCE_BITS + WORKER_ID_BITS + DATA_CENTER_ID_BITS;
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+
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+ // 固定数据中心 ID 和机器 ID
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+ private static final long DATA_CENTER_ID = 1;
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+ private static final long WORKER_ID = 1;
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+
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+ private static long sequence = 0L;
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+ private static long lastTimestamp = -1L;
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+
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+ public static synchronized long nextId() {
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+ long timestamp = System.currentTimeMillis();
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+
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+ if (timestamp < lastTimestamp) {
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+ throw new RuntimeException("Clock moved backwards. Refusing to generate id for " + (lastTimestamp - timestamp) + " milliseconds");
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+ }
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+
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+ if (timestamp == lastTimestamp) {
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+ sequence = (sequence + 1) & SEQUENCE_MASK;
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+ if (sequence == 0) {
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+ timestamp = waitForNextMillis(lastTimestamp);
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+ }
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+ } else {
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+ sequence = 0L;
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+ }
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+
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+ lastTimestamp = timestamp;
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+
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+ return ((timestamp - START_TIMESTAMP) << TIMESTAMP_LEFT_SHIFT) |
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+ (DATA_CENTER_ID << DATA_CENTER_ID_SHIFT) |
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+ (WORKER_ID << WORKER_ID_SHIFT) |
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+ sequence;
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+ }
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+
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+ private static long waitForNextMillis(long lastTimestamp) {
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+ long timestamp = System.currentTimeMillis();
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+ while (timestamp <= lastTimestamp) {
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+ timestamp = System.currentTimeMillis();
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+ }
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+ return timestamp;
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+ }
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+
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+ public static void main(String[] args) {
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+ for (int i = 0; i < 10; i++) {
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+ System.out.println(nextId());
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+ }
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+ }
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+}
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+
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