以下是使用 Spring Boot 实现雪花算法的完整代码。

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SnowflakeGeneratorApplication {

    public static void main(String[] args) {
        SpringApplication.run(SnowflakeGeneratorApplication.class, args);
    }

}

import org.springframework.stereotype.Component;

@Component
public class SnowflakeGenerator {
    
    private final long START_STMP = 1480166465631L;
 
    // 每部分占用的位数，注意不能超过63位，即 long 类型的最大位数
    private final long SEQUENCE_BIT = 12; // 序列号占用的位数
    private final long MACHINE_BIT = 5; // 机器标识占用的位数
    private final long DATACENTER_BIT = 5;// 数据中心占用的位数
 
    // 每部分最大值
    private final long MAX_DATACENTER_NUM = -1L ^ (-1L << DATACENTER_BIT);
    private final long MAX_MACHINE_NUM = -1L ^ (-1L << MACHINE_BIT);
    private final long MAX_SEQUENCE = -1L ^ (-1L << SEQUENCE_BIT);
 
    // 每部分向左的位移
    private final long MACHINE_LEFT = SEQUENCE_BIT;
    private final long DATACENTER_LEFT = SEQUENCE_BIT + MACHINE_BIT;
    private final long TIMESTMP_LEFT = DATACENTER_LEFT + DATACENTER_BIT;
 
    private long datacenterId; // 数据中心
    private long machineId; // 机器标识
    private long sequence = 0L; // 序列号
    private long lastStmp = -1L; // 上一次时间戳
 
    public SnowflakeGenerator() {
        this.datacenterId = getDatacenterId(MAX_DATACENTER_NUM);
        this.machineId = getMachineId(MAX_MACHINE_NUM);
    }
 
    public synchronized long nextId() {
        long currStmp = getNewstmp();
 
        if (currStmp < lastStmp) {
            throw new RuntimeException("Clock moved backwards.  Refusing to generate id");
        }
 
        if (currStmp == lastStmp) {
            sequence = (sequence + 1) & MAX_SEQUENCE;
            if (sequence == 0L) {
                currStmp = getNextMill();
            }
        } else {
            sequence = 0L;
        }
 
        lastStmp = currStmp;
 
        return (currStmp - START_STMP) << TIMESTMP_LEFT //
                | datacenterId << DATACENTER_LEFT // 数据中心部分
                | machineId << MACHINE_LEFT // 机器标识部分
                | sequence; // 序列号部分
    }
 
    private long getNextMill() {
        long mill = getNewstmp();
        while (mill <= lastStmp) {
            mill = getNewstmp();
        }
        return mill;
    }
 
    private long getNewstmp() {
        return System.currentTimeMillis();
    }
 
    /**
     * 获取 maxDatacenterId
     */
    protected long getDatacenterId(long maxDatacenterId) {
        long id = 0L;
        try {
            InetAddress ip = InetAddress.getLocalHost();
            NetworkInterface network = NetworkInterface.getByInetAddress(ip);
            if (network == null) {
                id = 1L;
            } else {
                byte[] mac = network.getHardwareAddress();
                if (mac != null) {
                    id = ((0x000000FF & (long) mac[mac.length - 1]) | (0x0000FF00 & (((long) mac[mac.length - 2]) << 8))) >> 6;
                    id = id % (maxDatacenterId + 1);
                }
            }
        } catch (Exception e) {
            System.out.println("get data center id error:" + e.getMessage());
        }
        return id;
    }
 
    /**
     * 获取 maxWorkerId
     */
    protected long getMachineId(long maxWorkerId) {
        long id = 0L;
        try {
            InetAddress ip = InetAddress.getLocalHost();
            NetworkInterface network = NetworkInterface.getByInetAddress(ip);
            if (network == null) {
                id = 1L;
            } else {
                byte[] mac = network.getHardwareAddress();
                if (mac != null) {
                    id = ((0x0000FF & (long) mac[mac.length - 2]) | (0x00FF00 & (((long) mac[mac.length - 1]) << 8))) >> 4;
                    id = id % (maxWorkerId + 1);
                }
            }
        } catch (Exception e) {
            System.out.println("get machine id error:" + e.getMessage());
        }
        return id;
    }
    
}

使用：

@Autowired
private SnowflakeGenerator snowflakeGenerator;

long id = snowflakeGenerator.nextId();