php雪花算法生成id,雪花算法如何生成id
雪花算法如何生成id
雪花算法生成id的方法：首先新建一个id生成的类；然后新建一个调用生成id的单例工具；最后使用函数【GuuidUtil.getUUID()】直接调用即可。
【相关学习推荐：java基础】
雪花算法生成id的方法：
1、新建一个id生成的类 SnowFlake/**
* @Auther: lyl
* @Date: 2019/11/21 17:49
* @Description:
*/
public class SnowFlake {
/**
* 起始的时间戳
*/
private final static long START_STMP = 1480166465631L;
/**
* 每一部分占用的位数
*/
private final static long SEQUENCE_BIT = 12; //序列号占用的位数
private final static long MACHINE_BIT = 5; //机器标识占用的位数
private final static long DATACENTER_BIT = 5;//数据中心占用的位数
/**
* 每一部分的最大值
*/
private final static long MAX_DATACENTER_NUM = -1L ^ (-1L << DATACENTER_BIT);
private final static long MAX_MACHINE_NUM = -1L ^ (-1L << MACHINE_BIT);
private final static long MAX_SEQUENCE = -1L ^ (-1L << SEQUENCE_BIT);
/**
* 每一部分向左的位移
*/
private final static long MACHINE_LEFT = SEQUENCE_BIT;
private final static long DATACENTER_LEFT = SEQUENCE_BIT + MACHINE_BIT;
private final static 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 SnowFlake(long datacenterId, long machineId) {
if (datacenterId > MAX_DATACENTER_NUM || datacenterId < 0) {
throw new IllegalArgumentException("datacenterId can't be greater than MAX_DATACENTER_NUM or less than 0");
}
if (machineId > MAX_MACHINE_NUM || machineId < 0) {
throw new IllegalArgumentException("machineId can't be greater than MAX_MACHINE_NUM or less than 0");
}
this.datacenterId = datacenterId;
this.machineId = machineId;
}
/**
* 产生下一个ID
*
* @return
*/
public synchronized long nextId() {
long currStmp = getNewstmp();
if (currStmp < lastStmp) {
throw new RuntimeException("Clock moved backwards. Refusing to generate id");
}
if (currStmp == lastStmp) {
//相同毫秒内，序列号自增
sequence = (sequence + 1) & MAX_SEQUENCE;
//同一毫秒的序列数已经达到最大
if (sequence == 0L) {
currStmp = getNextMill();
}
} else {
//不同毫秒内，序列号置为0
sequence = 0L;
}
lastStmp = currStmp;
return (currStmp - START_STMP) << TIMESTMP_LEFT //时间戳部分
| 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();
}
public static void main(String[] args) {
SnowFlake snowFlake = new SnowFlake(2, 3);
for (int i = 0; i < (1 << 12); i++) {
System.out.println(snowFlake.nextId());
}
}
}
2、为防止多线程生成重复的id，这边新建了一个调用生成id的单例工具
其中machineId和datacenterId可以放在配置文件中import java.util.concurrent.CountDownLatch;
/**
* @Auther: lyl
* @Date: 2019/11/21 18:15
* @Description:
*/
public class GuuidUtil {
private static long machineId = 0;
private static long datacenterId = 0;
/**
* 单例模式创建学法算法对象
* */
private enum SnowFlakeSingleton{
Singleton;
private SnowFlake snowFlake;
SnowFlakeSingleton(){
snowFlake = new SnowFlake(datacenterId,machineId);
}
public SnowFlake getInstance(){
return snowFlake;
}
}
public static long getUUID(){
return SnowFlakeSingleton.Singleton.getInstance().nextId();
}
public static void main(String[] args) {
CountDownLatch latch = new CountDownLatch(10000);
long start = System.currentTimeMillis();
for (int i = 0; i < 10000; i++) {
new Runnable() {
@Override
public void run() {
System.out.println(GuuidUtil.getUUID());
latch.countDown();
}
}.run();
}
try {
System.out.println("主线程"+Thread.currentThread().getName()+"等待子线程执行完成...");
latch.await();//阻塞当前线程，直到计数器的值为0
System.out.println("主线程"+Thread.currentThread().getName()+"开始执行...");
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.print("雪花算法用时： ");
System.out.println(System.currentTimeMillis() - start);
}
}
最后直接调用：GuuidUtil.getUUID()；就可以直接生成id想了解更多编程学习，敬请关注php培训栏目！
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