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 (jobob@qq.com).
*
* 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)
*
* 优化开源项目：https://gitee.com/yu120/sequence
*
*/
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 can't be greater than %d or less than 0", maxWorkerId));
// Assert.isFalse(datacenterId > maxDatacenterId || datacenterId < 0,
// String.format("datacenter Id can't 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 (jobob@qq.com).
*
* 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
*
* 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）
* System.currentTimeMillis()之所以慢是因为去跟系统打了一次交道
* 后台定时更新时钟，JVM退出时，线程自动回收
* 10亿：43410,206,210.72815533980582%
* 1亿：4699,29,162.0344827586207%
* 1000万：480,12,40.0%
* 100万：50,10,5.0%
*
*/
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。
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