package com.ruoyi.project.common;
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public class IdGeneratorUtils {
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// 时间戳左移的位数（22位给计数器）
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private static final long TIMESTAMP_SHIFT = 22;
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private static final long COUNTER_BITS = 22L;
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private static final long MAX_COUNTER = (1L << COUNTER_BITS) - 1;
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private static long lastTimestamp = -1L;
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private static long counter = 0L;
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public synchronized static long nextId() {
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long timestamp = System.currentTimeMillis();
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if (timestamp < lastTimestamp) {
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throw new RuntimeException("Clock moved backwards");
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}
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if (timestamp == lastTimestamp) {
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counter = (counter + 1) & MAX_COUNTER;
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if (counter == 0) {
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// 同一毫秒内计数器用完，等待下一毫秒
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timestamp = waitNextMillis(lastTimestamp);
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}
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} else {
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counter = 0L;
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}
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lastTimestamp = timestamp;
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return ((timestamp) << TIMESTAMP_SHIFT) | counter;
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}
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private static long waitNextMillis(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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