公司的雪花算法
作者：互联网
package com.ymm56.trade.order.center.biz.id.util;
/**
* snowflake改写的ID生成器实现
*/
class SnowflakeOrderIdGenerator implements OrderIdGenerator {
//private final long twepoch = 1481515932888L;//2016-12-12 12:12:12
//7位机器码
private final long workerIdBits = 8L;
//2位数据中心编码
private final long datacenterIdBits = 2L;
private final long maxWorkerId = -1L ^ (-1L << workerIdBits);
private final long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
//8位seq编码
private final long sequenceBits = 7L;
private final long workerIdShift = sequenceBits;
private final long datacenterIdShift = sequenceBits + workerIdBits;
private final long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;
private final long sequenceMask = -1L ^ (-1L << sequenceBits);
private long workerId;
//用于创建id的datacenterId
private long datacenterIdForCreate;
//用于替换id的datacenterId
private long datacenterIdForPlace;
private long sequence = 0L;
private long lastTimestamp = -1L;
// 现有的比较时间戳
private static final long COMPARE_TIME_PHASE_A = 1418741106341L;
// 到达老id后为了跳过老id段的时间戳
private static final long COMPARE_TIME_PHASE_B = 1414034077413L;
// 用现有方式到达老id的时间戳
private static final long OLD_ID_REACH_TIMESTAMP = 2149785353253L;
// 用于截取7位机器码（老ID是截取5位机器码+2位seq）
private static final int WORKID_SEQUENCE_TAIL = 0x7F;
// 用于截取最后8位（截取seq）
private static final int SEQUENCE_TAIL = 0xFF;
public SnowflakeOrderIdGenerator(long workerId, long datacenterIdForCreate, long datacenterIdForPlace) {
if (workerId > maxWorkerId || workerId < 0) {
throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0", maxWorkerId));
}
if (datacenterIdForCreate > maxDatacenterId || datacenterIdForCreate < 0) {
throw new IllegalArgumentException(String.format("datacenterIdForReplace Id can't be greater than %d or less than 0", maxDatacenterId));
}
if (datacenterIdForPlace > maxDatacenterId || datacenterIdForPlace < 0) {
throw new IllegalArgumentException(String.format("datacenterIdForReplace Id can't be greater than %d or less than 0", maxDatacenterId));
}
this.workerId = workerId;
this.datacenterIdForCreate = datacenterIdForCreate;
this.datacenterIdForPlace = datacenterIdForPlace;
}
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) {
sequence = (sequence + 1) & sequenceMask;
if (sequence == 0) {
timestamp = tilNextMillis(lastTimestamp);
}
} else {
sequence = 0L;
}
lastTimestamp = timestamp;
return (calTimestamp(timestamp) << timestampLeftShift) | (datacenterIdForCreate << datacenterIdShift) | (workerId << workerIdShift) | sequence;
}
/**
* 创建老Id的替换Id
* @param originId
* @return
*/
public synchronized long replaceId(long originId, long generateIncreaseId) {
// step 1 截取时间戳
long timestamp = originId >> timestampLeftShift;
// step 2 截取第9到15位（1、新发号器生成的ID是7位机器码 2、老发号器生成的ID是5位机器码+seq前两位)
long workTail = (originId >> sequenceBits) & WORKID_SEQUENCE_TAIL;
// step 3 截取sequence的后8位
long sequence = generateIncreaseId & SEQUENCE_TAIL;
return (timestamp << timestampLeftShift) | (datacenterIdForPlace << datacenterIdShift) | (workTail << workerIdShift) | sequence;
}
protected long tilNextMillis(long lastTimestamp) {
long timestamp = timeGen();
while (timestamp <= lastTimestamp) {
timestamp = timeGen();
}
return timestamp;
}
protected long timeGen() {
return System.currentTimeMillis();
}
/**
* 绕过可能碰撞上的Id，计算时间戳
* @param timestamp
* @return
*/
protected long calTimestamp(long timestamp){
long compareTimestamp = COMPARE_TIME_PHASE_A;
// 跳过现有的 95819431531254381 - 96436391095872324的订单id
if (timestamp > OLD_ID_REACH_TIMESTAMP) {
compareTimestamp = COMPARE_TIME_PHASE_B;
}
return timestamp - compareTimestamp;
}
public static long getTimeStampByOrderId(long orderId) {
return (orderId >> 17) + COMPARE_TIME_PHASE_A;
}
}
package com.ymm56.trade.order.center.biz.id.util;
import ocean.id.IPv4;
import ocean.id.NetUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* ID生成器工具类
*/
public class OrderIdUtil {
private static Logger logger = LoggerFactory.getLogger(ocean.id.IdUtil.class);
private static OrderIdGenerator orderIdGenerator;
private static long workerId = 1;
//用于生成新id时使用的datacenterId
private static long datacenterIdForCreate = 1;
//用于替换老id时使用的datacenterId
private static long datacenterIdForPlace = 3;
//ip取模值
private static int WORKER_ID_MO = 127;
private static OrderZkClient zkClient = OrderZkClient.getInstance();
//根节点
private static final String ID_CONFIG_PATH = "/YMM56/ORDERID/";
/**
* 生成Id
* @throws Exception
*/
public static synchronized long getId(String appName) throws Exception {
return getOrderIdGenerator(appName).nextId();
}
/**
* 替换Id
* @param appName
* @param originId
* @return
* @throws Exception
*/
public static synchronized long replaceId(String appName, long originId, long generateIncreaseId) throws Exception{
return getOrderIdGenerator(appName).replaceId(originId, generateIncreaseId);
}
/**
* 初始化 idGenerator
* @return
* @throws Exception
*/
private static synchronized OrderIdGenerator getOrderIdGenerator(String appName) throws Exception{
if(orderIdGenerator == null) {
workerId = getWorkerId(appName);
orderIdGenerator = new SnowflakeOrderIdGenerator(workerId, datacenterIdForCreate, datacenterIdForPlace);
}
return orderIdGenerator;
}
/**
* 获取workId
* @param appName
* @return
* @throws Exception
*/
private static long getWorkerId(String appName) throws Exception {
String ip = NetUtils.getFirstLocalIp();
String path = ID_CONFIG_PATH + appName;
Map<String, String> workerIdMap = new HashMap<>();
if (zkClient.exists(path)) {
List<String> childPath = zkClient.getChildren(path);
if (!CollectionUtils.isEmpty(childPath)) {
for (int i = 0; i < childPath.size(); i++) {
String existIp = zkClient.get(path + "/" + childPath.get(i));
if (!StringUtils.isEmpty(existIp)) {
if(existIp.equals(ip)){
return Integer.parseInt(childPath.get(i));
}
workerIdMap.put(childPath.get(i), existIp);
}
}
}
}
// workerId取机器ip转long后mod 127
workerId = IPv4.longValue(ip) % WORKER_ID_MO;
// workerId是否已被占用，如被占用直接+1循环遍历取下一个直到取到未被占用的workerId
int i = 0;
do {
String existIp = workerIdMap.get(workerId + "");
if (StringUtils.isEmpty(existIp)) {
if(zkClient.createIfNotExist(path + "/" + workerId + "", ip)){
logger.info("机器：[" + ip + "]计算出的workerId为：" + workerId);
return workerId;
}
}
workerId = workerId + 1;
workerId = (WORKER_ID_MO - workerId) >= 0 ? workerId : Math.abs(WORKER_ID_MO + 1 - workerId);
++i;
} while (i <= WORKER_ID_MO);
logger.error("workerId已经达到最大值，机器：[" + ip + "]使用workerId：" + workerId);
return workerId;
}
public static long getOrderCreateTimestamp(long orderId) {
return SnowflakeOrderIdGenerator.getTimeStampByOrderId(orderId);
}
}
标签：return,String,workerId,雪花,long,算法,static,private,公司 来源： https://www.cnblogs.com/juniorMa/p/15693159.html