雪花算法生成分布式主键ID

直接上代码，复制即可使用

public class SnowflakeIdGenerator {private static final long START_TIMESTAMP = 1624000000000L; // 设置起始时间戳，2021-06-18 00:00:00private static final long DATA_CENTER_ID_BITS = 5L;private static final long WORKER_ID_BITS = 5L;private static final long SEQUENCE_BITS = 12L;private static final long MAX_DATA_CENTER_ID = ~(-1L << DATA_CENTER_ID_BITS);private static final long MAX_WORKER_ID = ~(-1L << WORKER_ID_BITS);private static final long MAX_SEQUENCE = ~(-1L << SEQUENCE_BITS);private static final long DATA_CENTER_ID_SHIFT = SEQUENCE_BITS + WORKER_ID_BITS;private static final long WORKER_ID_SHIFT = SEQUENCE_BITS;private static final long TIMESTAMP_LEFT_SHIFT = SEQUENCE_BITS + WORKER_ID_BITS + DATA_CENTER_ID_BITS;private static long dataCenterId;private static long workerId;private static long sequence = 0L;private static long lastTimestamp = -1L;public static void init(long dataCenterId, long workerId) {if (dataCenterId > MAX_DATA_CENTER_ID || dataCenterId < 0) {throw new IllegalArgumentException(String.format("Data center ID can't be greater than %d or less than 0", MAX_DATA_CENTER_ID));}if (workerId > MAX_WORKER_ID || workerId < 0) {throw new IllegalArgumentException(String.format("Worker ID can't be greater than %d or less than 0", MAX_WORKER_ID));}SnowflakeIdGenerator.dataCenterId = dataCenterId;SnowflakeIdGenerator.workerId = workerId;}public static synchronized String generateId() {long timestamp = System.currentTimeMillis();if (timestamp < lastTimestamp) {throw new RuntimeException("Clock moved backwards. Refusing to generate id for " + (lastTimestamp - timestamp) + " milliseconds.");}if (timestamp == lastTimestamp) {sequence = (sequence + 1) & MAX_SEQUENCE;if (sequence == 0) {timestamp = waitNextMillis(timestamp);}} else {sequence = 0L;}lastTimestamp = timestamp;return String.valueOf(((timestamp - START_TIMESTAMP) << TIMESTAMP_LEFT_SHIFT)| (dataCenterId << DATA_CENTER_ID_SHIFT)| (workerId << WORKER_ID_SHIFT)| sequence);}private static long waitNextMillis(long timestamp) {long currentTimestamp = System.currentTimeMillis();while (currentTimestamp <= timestamp) {currentTimestamp = System.currentTimeMillis();}return currentTimestamp;}public static void main(String[] args) {SnowflakeIdGenerator.init(1, 1);for (int i = 0; i < 10; i++) {System.out.println("Snowflake ID: " + SnowflakeIdGenerator.generateId());}}
}

在这个示例中，你可以通过 SnowflakeIdGenerator.init(dataCenterId, workerId); 初始化数据中心 ID 和工作 ID，然后通过 SnowflakeIdGenerator.generateId(); 静态方法生成 Snowflake ID 的字符串形式。