自己写雪花算法IdWorker

package com.aiyusheng.shopping.util;

import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * <p>名称：IdWorker.java</p>
 * <p>描述：分布式自增长ID</p>
 * <pre>
 *     Twitter的 Snowflake　JAVA实现方案
 * </pre>
 * 核心代码为其IdWorker这个类实现，其原理结构如下，我分别用一个0表示一位，用—分割开部分的作用：
 * 1||0---0000000000 0000000000 0000000000 0000000000 0 --- 00000 ---00000 ---000000000000
 * 在上面的字符串中，第一位为未使用（实际上也可作为long的符号位），接下来的41位为毫秒级时间，
 * 然后5位datacenter标识位，5位机器ID（并不算标识符，实际是为线程标识），
 * 然后12位该毫秒内的当前毫秒内的计数，加起来刚好64位，为一个Long型。
 * 这样的好处是，整体上按照时间自增排序，并且整个分布式系统内不会产生ID碰撞（由datacenter和机器ID作区分），
 * 并且效率较高，经测试，snowflake每秒能够产生26万ID左右，完全满足需要。
 * <p>
 * 64位ID (42(毫秒)+5(机器ID)+5(业务编码)+12(重复累加))
 *
 * @author Polim
 */
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  WORKDER_ID_BITS = 5L;
    // 数据中心标识位数
    private final static long  DATACENTER_ID_BITS = 5L;
    // 机器ID最大值
    private final static long  MAX_WORKDER_ID= -1L ^ (-1L << WORKDER_ID_BITS);
    // 数据中心ID最大值
    private final static long  MAX_DATACENTER_ID= -1L ^ (-1L << DATACENTER_ID_BITS);
    // 毫秒内自增位
    private final static long  SEQUENCE_BITS= 12L;
    // 机器ID偏左移12位
    private final static long  WORKDER_ID_SHIFT= SEQUENCE_BITS;
    // 数据中心ID左移17位
    private final static long  DATACENTER_ID_SHIFT= SEQUENCE_BITS + WORKDER_ID_BITS;
    // 时间毫秒左移22位
    private final static long  TIMESTAMP_LEFT_SHIFT = SEQUENCE_BITS + WORKDER_ID_BITS + SEQUENCE_BITS;

    private final static long  SEQUENCE_MASK= -1L ^ (-1L << SEQUENCE_BITS);
    /* 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(MAX_DATACENTER_ID);
        this.workerId = getMaxWorkerId(datacenterId, MAX_WORKDER_ID);
    }
    /**
     * @param workerId
     *            工作机器ID
     * @param datacenterId
     *            序列号
     */
    public IdWorker(long workerId, long datacenterId) {
        if (workerId > MAX_WORKDER_ID || workerId < 0) {
            throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0", MAX_WORKDER_ID));
        }
        if (datacenterId > MAX_WORKDER_ID || datacenterId < 0) {
            throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0", MAX_DATACENTER_ID));
        }
        this.workerId = workerId;
        this.datacenterId = datacenterId;
    }
    /**
     * 获取下一个ID
     *
     * @return
     */
    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) & SEQUENCE_MASK;
            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) << TIMESTAMP_LEFT_SHIFT)
                | (datacenterId << DATACENTER_ID_SHIFT)
                | (workerId << WORKDER_ID_SHIFT) | sequence;

        return nextId;
    }

    /**
     * 功能描述： 自动补全生成32位
     * @Param:
     * @Return: java.lang.String
     * @Author: chenzhian
     * @Date: 2020/12/2 17:24
     * @Description:
     */
    public synchronized String next32Id(){
        String Id=  nextId()+"";
        String nowtime = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
        Integer surplusLength=32-Id.length()-nowtime.length();
        if(surplusLength>0){
            //自动补缺数字
            String strsurplus = String.format("%0"+surplusLength+"d", 0);
            return nowtime+strsurplus+Id;
        }else if(surplusLength==0){
            return nowtime+Id;
        }else{
            return nowtime.substring(0,(nowtime.length()+surplusLength))+Id;
        }
    }

    /**
     * 阻塞到下一个毫秒，直到获得新的时间戳
     * @param lastTimestamp 上次生成ID的时间截
     * @return 当前时间戳
     */
    private long tilNextMillis(final long lastTimestamp) {
        long timestamp = this.timeGen();
        while (timestamp <= lastTimestamp) {
            timestamp = this.timeGen();
        }
        return timestamp;
    }

    /**
     * 返回以毫秒为单位的当前时间
     * @return 当前时间(毫秒)
     */
    private long timeGen() {
        return System.currentTimeMillis();
    }

    /**
     * <p>
     * 获取 maxWorkerId
     * </p>
     */
    protected static long getMaxWorkerId(long datacenterId, long maxWorkerId) {
        StringBuffer mpid = new StringBuffer();
        mpid.append(datacenterId);
        String name = ManagementFactory.getRuntimeMXBean().getName();
        if (!name.isEmpty()) {
         /*
          * GET jvmPid
          */
            mpid.append(name.split("@")[0]);
        }
      /*
       * MAC + PID 的 hashcode 获取16个低位
       */
        return (mpid.toString().hashCode() & 0xffff) % (maxWorkerId + 1);
    }

    /**
     * <p>
     * 数据标识id部分
     * </p>
     */
    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;
    }


}

package com.aiyusheng.shopping.config;

import org.springframework.boot.context.properties.ConfigurationProperties;


@ConfigurationProperties(prefix = "ly.worker")
public class IdWorkerProperties {

    private long workerId;// 当前机器id

    private long datacenterId;// 序列号

    public long getWorkerId() {
        return workerId;
    }

    public void setWorkerId(long workerId) {
        this.workerId = workerId;
    }

    public long getDatacenterId() {
        return datacenterId;
    }

    public void setDatacenterId(long datacenterId) {
        this.datacenterId = datacenterId;
    }
}

package com.aiyusheng.shopping.config;

import com.aiyusheng.shopping.util.IdWorker;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
@EnableConfigurationProperties(IdWorkerProperties.class)
public class IdWorkerConfig {

    @Bean
    public IdWorker idWorker(IdWorkerProperties prop) {
        return new IdWorker(prop.getWorkerId(), prop.getDatacenterId());
    }
}

配置文件application.properties

ly.worker.workerId=1
ly.worker.datacenterId=1