雪花算法主键生成器

• Z时代
• 2024-01-10
• 分类：综合

IdWorker

package com.topnet.utils;
import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.NetworkInterface;
public class IdWorker {
  // 时间起始标记点，作为基准，一般取系统的最近时间（一旦确定不能变动）
  private final static long twepoch = 1288834974657L;
  // 机器标识位数
  private final static long workerIdBits = 5L;
  // 数据中心标识位数
  private final static long datacenterIdBits = 5L;
  // 机器ID最大值
  private final static long maxWorkerId = -1L ^ (-1L << workerIdBits);
  // 数据中心ID最大值
  private final static long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
  // 毫秒内自增位
  private final static long sequenceBits = 12L;
  // 机器ID偏左移12位
  private final static long workerIdShift = sequenceBits;
  // 数据中心ID左移17位
  private final static long datacenterIdShift = sequenceBits + workerIdBits;
  // 时间毫秒左移22位
  private final static long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;
  private final static long sequenceMask = -1L ^ (-1L << sequenceBits);
  /* 上次生产id时间戳 */
  private static long lastTimestamp = -1L;
  // 0，并发控制
  private long sequence = 0L;
  private final long workerId;
  // 数据标识id部分
  private final long datacenterId;
  public IdWorker() {
    this.datacenterId = getDatacenterId(maxDatacenterId);
    this.workerId = getMaxWorkerId(datacenterId, maxWorkerId);
  }
  /**
   * @param workerId 节点id
   * @param datacenterId 数据中心标识
   */
  public IdWorker(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) {
      // 当前毫秒内，则+1
      sequence = (sequence + 1) & sequenceMask;
      if (sequence == 0) {
        // 当前毫秒内计数满了，则等待下一秒
        timestamp = tilNextMillis(lastTimestamp);
      }
    } else {
      sequence = 0L;
    }
    lastTimestamp = timestamp;
    // ID偏移组合生成最终的ID，并返回ID
    long nextId = ((timestamp - twepoch) << timestampLeftShift)
        | (datacenterId << datacenterIdShift) | (workerId << workerIdShift) | sequence;
    return nextId;
  }
  private long tilNextMillis(final long lastTimestamp) {
    long timestamp = this.timeGen();
    while (timestamp <= lastTimestamp) {
      timestamp = this.timeGen();
    }
    return timestamp;
  }
  private long timeGen() {
    return System.currentTimeMillis();
  }
  /**
   * 
   * 获取 maxWorkerId
   */
  protected static long getMaxWorkerId(long datacenterId, long maxWorkerId) {
    StringBuffer mpid = new StringBuffer();
    mpid.append(datacenterId);
    String name = ManagementFactory.getRuntimeMXBean().getName();
    if (!name.isEmpty()) {
      mpid.append(name.split("@")[0]);
    }
    return (mpid.toString().hashCode() & 0xffff) % (maxWorkerId + 1);
  }
  /**
   * 
   * 数据标识id部分
   */
  protected static 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();
        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(" getDatacenterId: " + e.getMessage());
    }
    return id;
  }
  public static void main(String[] args) {
    System.out.println(System.getProperty("aaa"));
    IdWorker idWorker = new IdWorker(0, 0);
    for (int i = 0; i < 1; i++) {
      Long nextId = idWorker.nextId();
      System.out.println(Long.toBinaryString(nextId).length());
      System.out.println(nextId.toString().length());
    }
  }
}

KeyUtil

package com.topnet.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
 * 算法" title="雪花算法">雪花算法主键生成器
 * 
 * @author lpf 主键生成器
 */
public class KeyUtil {
  static Logger logger = LoggerFactory.getLogger(KeyUtil.class);
  static IdWorker s = null;
  static {
    Long datacenterId = null;
    Long workerId = null;
    try {
      datacenterId = Long.valueOf(System.getProperty("datacenterId"));
      workerId = Long.valueOf(System.getProperty("workerId"));
    } catch (Exception e) {
    }
    if (datacenterId == null && workerId == null) {
      logger.error("请在启动参数里配置-DdatacenterId=1 -DworkerId=1 ");
      s = new IdWorker();
    } else {
      s = new IdWorker(workerId, datacenterId);
    }
  }
  /**
   * 生成19位主键
   * 
   * @return
   */
  public static String getStrKey() {
    return String.valueOf(getLongKey());
  }
  /**
   * 生成19位主键
   * 
   * @return
   */
  public static Long getLongKey() {
    return s.nextId();
  }
  public static void main(String[] args) {
    while (true) {
      String key = getStrKey();
      if (key.length() == 19) {
        System.out.println(key);
        break;
      }
    }
  }
}

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