mybatis-plus分布式ID实现.rar

package com.movebrick.mybatisplus.toolkit; import org.apache.commons.lang3.StringUtils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; 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> * * @author hubin * @since 2016-08-18 */ public class Sequence { private static final Log logger = LogFactory.getLog(Sequence.class); /** * 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 static 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 (StringUtils.isNotBlank(name)) { /* * GET jvmPid */ mpid.append(name.split(StringPool.AT)[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 - 2 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(); } /** * 反解id的时间戳部分 */ public static long parseIdTimestamp(long id) { return (id>>22)+twepoch; } }