quarkus下的分布式ID怎么实现

Posted 2022-07-14 weir2010

说是quarkus的分布式ID是一种错误的说法，目前在java普遍的框架使用的分布式ID都是ORM框架提供的比如hibernate，jpa，mybatis-plus等，是spring框架还是quarkus还是别的没关系。

所以在java领域的分布式ID实现方式基本都一样quarkus也不例外。

今天要说的就是基于hibernate的一个接口扩展实现的，这个接口就是

org.hibernate.id.IdentifierGenerator;

那所以说jpa依赖的也是这个扩展而没有自己的扩展。

那有人说还区分hibernate和jpa么？是的。是有区分的：

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

import org.hibernate.annotations.GenericGenerator;

大家看这段引入就知道他们的分别。

好现在我们说下怎么实现分布式ID的，首先看扩展：

package com.weir.quarkus.base.system.entity;

import org.hibernate.HibernateException;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.id.IdentifierGenerator;

import com.weir.quarkus.base.system.utils.Sequence;

import java.io.Serializable;

public class MyIdGenerator implements IdentifierGenerator 
  private final Sequence sequence = new Sequence(null);
    @Override
    public Serializable generate(SharedSessionContractImplementor session, Object object) throws HibernateException 
        return sequence.nextId();
    

这里依赖了Sequence：

/*
 * Copyright (c) 2011-2022, baomidou
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.weir.quarkus.base.system.utils;

import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.concurrent.ThreadLocalRandom;

/**
 * 分布式高效有序 ID 生产黑科技(sequence)
 *
 * <p>优化开源项目：https://gitee.com/yu120/sequence</p>
 *

 */
public class Sequence 

    /**
     * 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 long twepoch = 1288834974657L;
    /**
     * 机器标识位数
     */
    private final long workerIdBits = 5L;
    private final long datacenterIdBits = 5L;
    private final long maxWorkerId = -1L ^ (-1L << workerIdBits);
    private final long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
    /**
     * 毫秒内自增位
     */
    private final long sequenceBits = 12L;
    private final long workerIdShift = sequenceBits;
    private final long datacenterIdShift = sequenceBits + workerIdBits;
    /**
     * 时间戳左移动位
     */
    private final long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;
    private final long sequenceMask = -1L ^ (-1L << sequenceBits);

    private final long workerId;

    /**
     * 数据标识 ID 部分
     */
    private final long datacenterId;
    /**
     * 并发控制
     */
    private long sequence = 0L;
    /**
     * 上次生产 ID 时间戳
     */
    private long lastTimestamp = -1L;
    /**
     * IP 地址
     */
    private InetAddress inetAddress;

    public Sequence(InetAddress inetAddress) 
        this.inetAddress = inetAddress;
        this.datacenterId = getDatacenterId(maxDatacenterId);
        this.workerId = getMaxWorkerId(datacenterId, maxWorkerId);
    

    /**
     * 有参构造器
     *
     * @param workerId     工作机器 ID
     * @param datacenterId 序列号
     */
    public Sequence(long workerId, long datacenterId) 
//        Assert.isFalse(workerId > maxWorkerId || workerId < 0,
//            String.format("worker Id cant be greater than %d or less than 0", maxWorkerId));
//        Assert.isFalse(datacenterId > maxDatacenterId || datacenterId < 0,
//            String.format("datacenter Id cant be greater than %d or less than 0", maxDatacenterId));
        this.workerId = workerId;
        this.datacenterId = datacenterId;
    

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

    /**
     * 数据标识id部分
     */
    protected long getDatacenterId(long maxDatacenterId) 
        long id = 0L;
        try 
            if (null == this.inetAddress) 
                this.inetAddress = InetAddress.getLocalHost();
            
            NetworkInterface network = NetworkInterface.getByInetAddress(this.inetAddress);
            if (null == network) 
                id = 1L;
             else 
                byte[] mac = network.getHardwareAddress();
                if (null != mac) 
                    id = ((0x000000FF & (long) mac[mac.length - 2]) | (0x0000FF00 & (((long) mac[mac.length - 1]) << 8))) >> 6;
                    id = id % (maxDatacenterId + 1);
                
            
         catch (Exception e) 
//            logger.warn(" getDatacenterId: " + e.getMessage());
        
        return id;
    

    /**
     * 获取下一个 ID
     *
     * @return 下一个 ID
     */
    public synchronized long nextId() 
        long timestamp = timeGen();
        //闰秒
        if (timestamp < lastTimestamp) 
            long offset = lastTimestamp - timestamp;
            if (offset <= 5) 
                try 
                    wait(offset << 1);
                    timestamp = timeGen();
                    if (timestamp < lastTimestamp) 
                        throw new RuntimeException(String.format("Clock moved backwards.  Refusing to generate id for %d milliseconds", offset));
                    
                 catch (Exception e) 
                    throw new RuntimeException(e);
                
             else 
                throw new RuntimeException(String.format("Clock moved backwards.  Refusing to generate id for %d milliseconds", offset));
            
        

        if (lastTimestamp == timestamp) 
            // 相同毫秒内，序列号自增
            sequence = (sequence + 1) & sequenceMask;
            if (sequence == 0) 
                // 同一毫秒的序列数已经达到最大
                timestamp = tilNextMillis(lastTimestamp);
            
         else 
            // 不同毫秒内，序列号置为 1 - 3 随机数
            sequence = ThreadLocalRandom.current().nextLong(1, 3);
        

        lastTimestamp = timestamp;

        // 时间戳部分 | 数据中心部分 | 机器标识部分 | 序列号部分
        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 SystemClock.now();
    

大家如果对它陌生可以自己去了解，这个分布式ID的实现在java领域用的比较普遍。

/*
 * Copyright (c) 2011-2022, baomidou
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.weir.quarkus.base.system.utils;

import java.sql.Timestamp;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

/**
 * 高并发场景下System.currentTimeMillis()的性能问题的优化
 *
 * <p>System.currentTimeMillis()的调用比new一个普通对象要耗时的多（具体耗时高出多少我还没测试过，有人说是100倍左右）</p>
 * <p>System.currentTimeMillis()之所以慢是因为去跟系统打了一次交道</p>
 * <p>后台定时更新时钟，JVM退出时，线程自动回收</p>
 * <p>10亿：43410,206,210.72815533980582%</p>
 * <p>1亿：4699,29,162.0344827586207%</p>
 * <p>1000万：480,12,40.0%</p>
 * <p>100万：50,10,5.0%</p>
 *

 */
public class SystemClock 

    private final long period;
    private final AtomicLong now;

    private SystemClock(long period) 
        this.period = period;
        this.now = new AtomicLong(System.currentTimeMillis());
        scheduleClockUpdating();
    

    private static SystemClock instance() 
        return InstanceHolder.INSTANCE;
    

    public static long now() 
        return instance().currentTimeMillis();
    

    public static String nowDate() 
        return new Timestamp(instance().currentTimeMillis()).toString();
    

    private void scheduleClockUpdating() 
        ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor(runnable -> 
            Thread thread = new Thread(runnable, "System Clock");
            thread.setDaemon(true);
            return thread;
        );
        scheduler.scheduleAtFixedRate(() -> now.set(System.currentTimeMillis()), period, period, TimeUnit.MILLISECONDS);
    

    private long currentTimeMillis() 
        return now.get();
    

    private static class InstanceHolder 
        public static final SystemClock INSTANCE = new SystemClock(1);
    

这个类解释的也比较明显。高并发下生成ID的一些优化。

有了上面的我们怎么使用呢？两个注解就搞定了：

package com.weir.quarkus.base.system.entity;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

import org.hibernate.annotations.GenericGenerator;

@Entity
public class MumberUser extends BaseEntity 

  private static final long serialVersionUID = 7653528299072640929L;
  
  @Id
  @GenericGenerator(name = "my_id", strategy = "com.weir.quarkus.base.system.entity.MyIdGenerator" )
    @GeneratedValue(generator = "my_id")
  public Long id;
  public String name;
  public void setId(Long id) 
    this.id = id;
  
  
  

是不是比较简单，这样在quarkus框架下就可以拥有分布式ID了，大家好好消化下。