小编给大家分享一下java如何使用预分配法生成唯一ID，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
在项目中经常有生成唯一ID的业务需求。作为唯一标识方便后续查找和追踪。网上也有很多实现方案。比如：数据库自增主键，数据库批量生成ID，UUID，时间戳方法，zookeeper生成ID，redis生成唯一ID，snowflake算法等等。这些解决方案各有优缺点。我在游戏项目常用的解决方案是：预分配法生成唯一ID。其原理简单，利于扩展，具有较强的适用性。
预分配法生成唯一ID原理：数据库中存储每种类型最后的预分配dbUniqueId值。数据库实体对象上增加当前分配的
useDbUniqueId。预分配步长DBUNIQUEID_M可根据类型和业务量自定义。当useDbUniqueId大于等于dbUniqueId时就预分配出DBUNIQUEID_M个唯一ID。
角色ID生成：要求7位连续的唯一ID。则DBUNIQUEID_M=1。1000000+dbUniqueId格式化成7位数字。
本服唯一ID：则DBUNIQUEID_M=10000。(1000000+dbUniqueId)*10000+serverId格式化而成。其中serverId游戏服ID定义为4位
全局唯一ID：则DBUNIQUEID_M=10000。((100000000000L+dbUniqueId)100+gameCode10000+workerId;格式化而成。其中gameCode游戏编码定义为2位。
具体实现请参阅代码。非常方便的移植到项目工程中。
IdWorkerEnum.java
package com.game.common.db;import java.util.List;import com.core.enums.LLIndexedEnum;public enum IdWorkerEnum implements LLIndexedEnum{ IDWORKER_HUMANID(1,"角色ID"), IDWORKER_DBID(2,"数据库ID"), IDWORKER_CLUBID(3,"工会ID"), IDWORKER_COLLECTID(4,"收集ID"),; public final int index; private final String nameKey; private static final List<IdWorkerEnum> indexes=LLIndexedEnum.IndexedEnumUtil.toIndexes(IdWorkerEnum.values()); private IdWorkerEnum(int index,String nameKey) { this.index=index; this.nameKey=nameKey; } @Override public int getIndex() { return index; } public String getNameKey() { return this.nameKey; } public static IdWorkerEnum valueOf(final int index) { return LLIndexedEnum.IndexedEnumUtil.valueOf(indexes,index); }}DbUniqueIdEntity.java
package com.game.common.db;import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.Id;import org.eclipse.persistence.annotations.HashPartitioning;import org.eclipse.persistence.annotations.Partitioned;import com.game.common.db.dao.BaseDbBean;@Entity(name="t_dbUniqueId")@HashPartitioning(name="HashPartitionByDbUniqueCacheId",partitionColumn=@Column(name="dbUniqueCacheId"))@Partitioned("HashPartitionByDbUniqueCacheId")public class DbUniqueIdEntity extends BaseDbBean{ @Id @Column(length=20) private long dbUniqueCacheId; @Column(length=20) private long dbUniqueId; @Column(length=20) private long createTime; // ////////////////内部数据////////////////// @Column(length=20) private long useDbUniqueId; @Override public long getId() { return dbUniqueCacheId; } @Override public void setId(long id) { } public long getDbUniqueCacheId() { return dbUniqueCacheId; } public void setDbUniqueCacheId(long dbUniqueCacheId) { this.dbUniqueCacheId=dbUniqueCacheId; } public long getDbUniqueId() { return dbUniqueId; } public void setDbUniqueId(long dbUniqueId) { this.dbUniqueId=dbUniqueId; } public long getCreateTime() { return createTime; } public void setCreateTime(long createTime) { this.createTime=createTime; } public long getUseDbUniqueId() { return useDbUniqueId; } public void setUseDbUniqueId(long useDbUniqueId) { this.useDbUniqueId=useDbUniqueId; }}IdWorker.java
package com.game.common.db;import com.game.common.Globals;import com.game.common.entityProxy.EntityProxy;import com.game.core.appConfig.AppConfigServ;import com.game.core.utils.LoggerUtils;public class IdWorker{ public final static IdWorker OBJ=new IdWorker(AppConfigServ.OBJ.getAppConfigBean().getServerNo()); private int DBUNIQUEID_M=2000; private final long workerId; private DbUniqueIdEntity[] szDbUniqueIdEntity=new DbUniqueIdEntity[5]; public IdWorker(long workerId) { this.workerId=workerId; } public synchronized long nextId() { IdWorkerEnum idWorkerEnum=IdWorkerEnum.IDWORKER_DBID; int dbUniqueCacheId=idWorkerEnum.getIndex(); loadDbUniqueId(idWorkerEnum); DbUniqueIdEntity dbUniqueIdEntity=szDbUniqueIdEntity[dbUniqueCacheId]; long dbUniqueId=0; // 需要重新分配Id:每次分配 M个 if(dbUniqueIdEntity.getUseDbUniqueId()>=dbUniqueIdEntity.getDbUniqueId()) { dbUniqueIdEntity.setDbUniqueId(dbUniqueIdEntity.getDbUniqueId()+DBUNIQUEID_M); EntityProxy.OBJ.update((long) dbUniqueCacheId,dbUniqueIdEntity); LoggerUtils.serverLogger.info("IdWorker DbId:update dbUniqueId="+dbUniqueIdEntity.getDbUniqueId()); } dbUniqueId=dbUniqueIdEntity.getUseDbUniqueId()+1; dbUniqueIdEntity.setUseDbUniqueId(dbUniqueId); // 11位UUID return (1000000+dbUniqueId)*10000+workerId; } public synchronized long nextHumanId() { IdWorkerEnum idWorkerEnum=IdWorkerEnum.IDWORKER_HUMANID; int dbUniqueCacheId=idWorkerEnum.getIndex(); loadDbUniqueId(idWorkerEnum); DbUniqueIdEntity dbUniqueIdEntity=szDbUniqueIdEntity[dbUniqueCacheId]; long dbUniqueId=0; // 需要重新分配Id:每次分配 M个 if(dbUniqueIdEntity.getUseDbUniqueId()>=dbUniqueIdEntity.getDbUniqueId()) { dbUniqueIdEntity.setDbUniqueId(dbUniqueIdEntity.getDbUniqueId()+1); EntityProxy.OBJ.update((long) dbUniqueCacheId,dbUniqueIdEntity); LoggerUtils.serverLogger.info("IdWorker HumanId:update dbUniqueId="+dbUniqueIdEntity.getDbUniqueId()); } dbUniqueId=dbUniqueIdEntity.getUseDbUniqueId()+1; dbUniqueIdEntity.setUseDbUniqueId(dbUniqueId); // 7位UUID return (1000000+dbUniqueId); } public synchronized long nextClubId() { IdWorkerEnum idWorkerEnum=IdWorkerEnum.IDWORKER_CLUBID; int dbUniqueCacheId=idWorkerEnum.getIndex(); loadDbUniqueId(idWorkerEnum); DbUniqueIdEntity dbUniqueIdEntity=szDbUniqueIdEntity[dbUniqueCacheId]; long dbUniqueId=0; // 需要重新分配Id:每次分配 M个 if(dbUniqueIdEntity.getUseDbUniqueId()>=dbUniqueIdEntity.getDbUniqueId()) { dbUniqueIdEntity.setDbUniqueId(dbUniqueIdEntity.getDbUniqueId()+1); EntityProxy.OBJ.update((long) dbUniqueCacheId,dbUniqueIdEntity); LoggerUtils.serverLogger.info("IdWorker clubId:update dbUniqueId="+dbUniqueIdEntity.getDbUniqueId()); } dbUniqueId=dbUniqueIdEntity.getUseDbUniqueId()+1; dbUniqueIdEntity.setUseDbUniqueId(dbUniqueId); // 5位UUID return (10000+dbUniqueId); } public synchronized long nextCollectId() { IdWorkerEnum idWorkerEnum=IdWorkerEnum.IDWORKER_COLLECTID; int dbUniqueCacheId=idWorkerEnum.getIndex(); loadDbUniqueId(idWorkerEnum); DbUniqueIdEntity dbUniqueIdEntity=szDbUniqueIdEntity[dbUniqueCacheId]; long dbUniqueId=0; // 需要重新分配Id:每次分配 M个 if(dbUniqueIdEntity.getUseDbUniqueId()>=dbUniqueIdEntity.getDbUniqueId()) { dbUniqueIdEntity.setDbUniqueId(dbUniqueIdEntity.getDbUniqueId()+DBUNIQUEID_M); EntityProxy.OBJ.update((long) dbUniqueCacheId,dbUniqueIdEntity); LoggerUtils.serverLogger.info("IdWorker DbId:update dbUniqueId="+dbUniqueIdEntity.getDbUniqueId()); } dbUniqueId=dbUniqueIdEntity.getUseDbUniqueId()+1; dbUniqueIdEntity.setUseDbUniqueId(dbUniqueId); // 18位UUID:游戏ID+服务器ID。确保支持多游戏不重复的ID。便于兼容统计 return ((100000000000L+dbUniqueId)*100+AppConfigServ.OBJ.getAppConfigBean().getGameCode())*10000+workerId; } public void loadDbUniqueId(IdWorkerEnum idWorkerEnum) { int dbUniqueCacheId=idWorkerEnum.getIndex(); if(szDbUniqueIdEntity[dbUniqueCacheId]!=null) return; DbUniqueIdEntity dbUniqueIdEntity=EntityProxy.OBJ.get((long) dbUniqueCacheId,(long) dbUniqueCacheId,DbUniqueIdEntity.class); if(dbUniqueIdEntity==null) { dbUniqueIdEntity=new DbUniqueIdEntity(); dbUniqueIdEntity.setDbUniqueCacheId(dbUniqueCacheId); dbUniqueIdEntity.setDbUniqueId(0); dbUniqueIdEntity.setCreateTime(Globals.getTimeService().now()); dbUniqueIdEntity.setUseDbUniqueId(0); EntityProxy.OBJ.insert((long) dbUniqueCacheId,dbUniqueIdEntity); } dbUniqueIdEntity.setUseDbUniqueId(dbUniqueIdEntity.getDbUniqueId()); szDbUniqueIdEntity[dbUniqueCacheId]=dbUniqueIdEntity; LoggerUtils.serverLogger.info("IdWorker:load dbUniqueId="+dbUniqueIdEntity.getDbUniqueId()); }}以上是“java如何使用预分配法生成唯一ID”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注编程网行业资讯频道！
