lanyuanxiaoyao/spring-boot-service-template
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refactor(jpa): 将 Snowflake ID 生成逻辑抽取为公共工具类

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兰缘小妖
2026-01-07 09:47:42 +08:00
parent 1d6a08a16f
commit 5bf6e9ecdc
2 changed files with 70 additions and 67 deletions
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68
spring-boot-service-template-common/src/main/java/com/lanyuanxiaoyao/service/template/common/helper/SnowflakeHelper.java Normal file
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@@ -0,0 +1,68 @@
package com.lanyuanxiaoyao.service.template.common.helper;
import java.time.Instant;
public class SnowflakeHelper {
/**
* 起始的时间戳
*/
private final static long START_TIMESTAMP = 1;
/**
* 序列号占用的位数
*/
private final static long SEQUENCE_BIT = 11;
/**
* 序列号最大值
*/
private final static long MAX_SEQUENCE_BIT = ~(-1 << SEQUENCE_BIT);
/**
* 时间戳值向左位移
*/
private final static long TIMESTAMP_OFFSET = SEQUENCE_BIT;
/**
* 序列号
*/
private static long sequence = 0;
/**
* 上一次时间戳
*/
private static long lastTimestamp = -1;
public static synchronized long next() {
long currentTimestamp = nowTimestamp();
if (currentTimestamp < lastTimestamp) {
throw new RuntimeException("Clock have moved backwards.");
}
if (currentTimestamp == lastTimestamp) {
// 相同毫秒内, 序列号自增
sequence = (sequence + 1) & MAX_SEQUENCE_BIT;
// 同一毫秒的序列数已经达到最大
if (sequence == 0) {
currentTimestamp = nextTimestamp();
}
} else {
// 不同毫秒内, 序列号置为0
sequence = 0;
}
lastTimestamp = currentTimestamp;
return (currentTimestamp - START_TIMESTAMP) << TIMESTAMP_OFFSET | sequence;
}
private static long nextTimestamp() {
long milli = nowTimestamp();
while (milli <= lastTimestamp) {
milli = nowTimestamp();
}
return milli;
}
private static long nowTimestamp() {
return Instant.now().toEpochMilli();
}
}

69
spring-boot-service-template-jpa/src/main/java/com/lanyuanxiaoyao/service/template/jpa/entity/SnowflakeIdGenerator.java
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@@ -1,7 +1,7 @@
package com.lanyuanxiaoyao.service.template.jpa.entity;
import com.lanyuanxiaoyao.service.template.common.helper.SnowflakeHelper;
import java.io.Serializable;
import java.time.Instant;
import lombok.extern.slf4j.Slf4j;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.id.IdentifierGenerator;
@@ -11,75 +11,10 @@ public class SnowflakeIdGenerator implements IdentifierGenerator {
@Override
public Serializable generate(SharedSessionContractImplementor session, Object object) {
try {
return Snowflake.next();
return SnowflakeHelper.next();
} catch (Exception e) {
log.error("Generate snowflake id failed", e);
throw new RuntimeException(e);
}
}
public static class Snowflake {
/**
* 起始的时间戳
*/
private final static long START_TIMESTAMP = 1;
/**
* 序列号占用的位数
*/
private final static long SEQUENCE_BIT = 11;
/**
* 序列号最大值
*/
private final static long MAX_SEQUENCE_BIT = ~(-1 << SEQUENCE_BIT);
/**
* 时间戳值向左位移
*/
private final static long TIMESTAMP_OFFSET = SEQUENCE_BIT;
/**
* 序列号
*/
private static long sequence = 0;
/**
* 上一次时间戳
*/
private static long lastTimestamp = -1;
public static synchronized long next() {
long currentTimestamp = nowTimestamp();
if (currentTimestamp < lastTimestamp) {
throw new RuntimeException("Clock have moved backwards.");
}
if (currentTimestamp == lastTimestamp) {
// 相同毫秒内, 序列号自增
sequence = (sequence + 1) & MAX_SEQUENCE_BIT;
// 同一毫秒的序列数已经达到最大
if (sequence == 0) {
currentTimestamp = nextTimestamp();
}
} else {
// 不同毫秒内, 序列号置为0
sequence = 0;
}
lastTimestamp = currentTimestamp;
return (currentTimestamp - START_TIMESTAMP) << TIMESTAMP_OFFSET | sequence;
}
private static long nextTimestamp() {
long milli = nowTimestamp();
while (milli <= lastTimestamp) {
milli = nowTimestamp();
}
return milli;
}
private static long nowTimestamp() {
return Instant.now().toEpochMilli();
}
}
}