Java分布式ID中Snowflake雪花算法应用实现

import org.springframework.stereotype.Service;  
  
@Service  
public class SnowflakeIdWorker {  
    // 初始化参数  
    private final long twepoch = 1288834974657L;  
    private long workerId;  
    private long datacenterId;  
    private long sequence = 0L;  
  
    private final long workerIdBits = 5L;  
    private final long datacenterIdBits = 5L;  
    private final long maxWorkerId = -1L ^ (-1L << workerIdBits);  
    private final long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);  
    private final long sequenceBits = 12L;  
  
    private final long workerIdShift = sequenceBits;  
    private final long datacenterIdShift = sequenceBits + workerIdBits;  
    private final long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;  
    private final long sequenceMask = -1L ^ (-1L << sequenceBits);  
  
    private long lastTimestamp = -1L;  
  
    public SnowflakeIdWorker(long workerId, long datacenterId) {  
        if (workerId > maxWorkerId || workerId < 0) {  
            throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0", maxWorkerId));  
        }  
        if (datacenterId > maxDatacenterId || datacenterId < 0) {  
            throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0", maxDatacenterId));  
        }  
        this.workerId = workerId;  
        this.datacenterId = datacenterId;  
    }  
  
    public synchronized long nextId() {  
        long timestamp = timeGen();  
  
        if (timestamp < lastTimestamp) {  
            throw new RuntimeException(String.format("Clock moved backwards.  Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));  
        }  
  
        if (lastTimestamp == timestamp) {  
            sequence = (sequence + 1) & sequenceMask;  
            if (sequence == 0) {  
                timestamp = tilNextMillis(lastTimestamp);  
            }  
        } else {  
            sequence = 0L;  
        }  
  
        lastTimestamp = timestamp;  
  
        return ((timestamp - twepoch) << timestampLeftShift) |  
                (datacenterId << datacenterIdShift) |  
                (workerId << workerIdShift) |  
                sequence;  
    }  
  
    protected long tilNextMillis(long lastTimestamp) {  
        long timestamp = timeGen();  
        while (timestamp <= lastTimestamp) {  
            timestamp = timeGen();  
        }
   		return timestamp;
	}

	protected long timeGen() {  
	    return System.currentTimeMillis();  
	}
}

import org.springframework.context.annotation.Bean;  
import org.springframework.context.annotation.Configuration;  
  
@Configuration  
public class SnowflakeConfig {  
  
    @Bean  
    public SnowflakeIdWorker snowflakeIdWorker() {  
        // 根据实际部署情况设置工作机器ID和数据中心ID  
        long workerId = 1L;  
        long datacenterId = 1L;  
        return new SnowflakeIdWorker(workerId, datacenterId);  
    }  
}

import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.stereotype.Service;  
  
@Service  
public class SomeService {  
  
    private final SnowflakeIdWorker snowflakeIdWorker;  
  
    @Autowired  
    public SomeService(SnowflakeIdWorker snowflakeIdWorker) {  
        this.snowflakeIdWorker = snowflakeIdWorker;  
    }  
  
    public void someMethod() {  
        long id = snowflakeIdWorker.nextId();  
        // 使用生成的ID进行后续操作  
    }  
}