话不多说，直接上代码

代码

POM

1. <!-- Web -->
2. <dependency>
3. <groupId>org.springframework.boot</groupId>
4. <artifactId>spring-boot-starter-web</artifactId>
5. </dependency>
6. <!-- MySQL驱动 -->
7. <dependency>
8. <groupId>com.mysql</groupId>
9. <artifactId>mysql-connector-j</artifactId>
10. <scope>runtime</scope>
11. </dependency>
12. <!-- MybatisPlus -->
13. <dependency>
14. <groupId>com.baomidou</groupId>
15. <artifactId>mybatis-plus-spring-boot3-starter</artifactId>
16. <version>3.5.9</version>
17. </dependency>
18. <!-- Redisson -->
19. <dependency>
20. <groupId>org.redisson</groupId>
21. <artifactId>redisson-spring-boot-starter</artifactId>
22. <version>3.39.0</version>
23. </dependency>

自定义ID生成器

1. import java.util.concurrent.TimeUnit;
3. import org.redisson.api.RAtomicLong;
4. import org.redisson.api.RLock;
5. import org.redisson.api.RedissonClient;
6. import org.springframework.data.redis.core.StringRedisTemplate;
7. import org.springframework.scheduling.annotation.EnableScheduling;
8. import org.springframework.scheduling.annotation.Scheduled;
9. import org.springframework.stereotype.Component;
11. import com.baomidou.mybatisplus.core.incrementer.IdentifierGenerator;
12. import com.baomidou.mybatisplus.core.toolkit.Sequence;
14. import jakarta.annotation.Resource;
15. import lombok.extern.slf4j.Slf4j;
17. @Slf4j
18. @EnableScheduling
19. @Component
20. public class SnowflakeIdGenerator implements IdentifierGenerator {
22. @Resource
23. private RedissonClient redissonClient;
25. @Resource
26. private StringRedisTemplate stringRedisTemplate;
28. @Override
29. public Number nextId(Object entity) {
30. return getSequence().nextId();
31. }
33. private volatile Sequence sequence;
35. private Long id;
37. public Sequence getSequence() {
38. if (sequence == null) {
39. synchronized (SnowflakeIdGenerator.class) {
40. if (sequence == null) {
41. RLock lock = redissonClient.getLock("snowflake:lock");
42. try {
43. if (lock.tryLock(10, 10, TimeUnit.SECONDS)) {
44. RAtomicLong atomicLong = redissonClient.getAtomicLong("snowflake:id");
45. // 最终获取的序号ID
46. long id;
47. // 累计获取的次数
48. int i = 0;
49. do {
50. i++;
51. // 如果累计获取超过1024次，则说明没有可以使用的ID了，抛出异常
52. if (i > 1024) {
53. log.error("获取不到可以使用的雪花ID序号");
54. throw new RuntimeException("获取不到可以使用的雪花ID序号");
55. }
56. // 获取ID
57. id = atomicLong.incrementAndGet();
58. if (id >= 1024) {
59. id = 0;
60. atomicLong.set(0);
61. }
62. // 检查是否已被占用
63. String watchDogKey = "snowflake:id:" + id;
64. if (stringRedisTemplate.hasKey(watchDogKey)) {
65. log.warn("当前雪花ID序号：{}已被使用", id);
66. } else {
67. // 未使用，设置占用标记
68. stringRedisTemplate.opsForValue().set(watchDogKey, "", 65, TimeUnit.SECONDS);
69. this.id = id;
70. break;
71. }
72. } while (true);
73. long workerId = id / 32;
74. long datacenterId = id % 32;
75. log.info("当前雪花ID序号为：{},对应的workerId为：{},对应的datacenterId为：{}", id, workerId, datacenterId);
76. sequence = new Sequence(workerId, datacenterId);
77. }
78. } catch (InterruptedException e) {
79. throw new RuntimeException(e);
80. } finally {
81. if (lock.isLocked() && lock.isHeldByCurrentThread()) {
82. lock.unlock();
83. log.debug("lock released");
84. }
85. }
86. }
87. }
88. }
89. return sequence;
90. }
92. @Scheduled(fixedDelay = 20000)
93. public void scheduledTask() {
94. if (id == null) {
95. log.debug("雪花ID序号未初始化，无需执行");
96. return;
97. }
98. // 更新占用
99. stringRedisTemplate.opsForValue().set("snowflake:id:" + id, "", 65, TimeUnit.SECONDS);
100. }
102. }

测试

实体

1. import java.io.Serializable;
3. import com.baomidou.mybatisplus.annotation.IdType;
4. import com.baomidou.mybatisplus.annotation.TableId;
5. import com.baomidou.mybatisplus.annotation.TableName;
6. import com.baomidou.mybatisplus.extension.activerecord.Model;
8. import lombok.Getter;
9. import lombok.NoArgsConstructor;
10. import lombok.Setter;
11. import lombok.ToString;
12. import lombok.experimental.Accessors;
14. /**
15. * 示例
16. *
17. * @author Max_Qiu
18. */
19. @Getter
20. @Setter
21. @NoArgsConstructor
22. @ToString
23. @Accessors(chain = true)
24. @TableName("demo")
25. public class Demo extends Model<Demo> {
27. /**
28. * 主键ID
29. */
30. @TableId(value = "id", type = IdType.ASSIGN_ID)
31. private Long id;
33. @Override
34. public Serializable pkVal() {
35. return this.id;
36. }
38. }

测试类

1. import java.util.concurrent.ExecutorService;
2. import java.util.concurrent.Executors;
3. import java.util.concurrent.TimeUnit;
5. import org.junit.jupiter.api.Test;
6. import org.springframework.boot.test.context.SpringBootTest;
8. import com.maxqiu.demo.entity.Demo;
10. /**
11. * @author Max_Qiu
12. */
13. @SpringBootTest
14. class DemoServiceTest {
16. @Test
17. void insert() throws InterruptedException {
18. ExecutorService executorService = Executors.newCachedThreadPool();
19. for (int i = 0; i < 3; i++) {
20. executorService.execute(() -> {
21. Demo demo = new Demo();
22. demo.insert();
23. System.out.println(demo.getId());
24. });
25. }
26. executorService.shutdown();
27. executorService.awaitTermination(5, TimeUnit.SECONDS);
28. }
30. }

输出

1. 2024-12-15T18:58:00.882+08:00 INFO 15392 --- [pool-2-thread-3] c.m.demo.config.SnowflakeIdGenerator : 当前雪花ID序号为：26,对应的workerId为：0,对应的datacenterId为：26
2. 2024-12-15T18:58:00.902+08:00 INFO 15392 --- [pool-2-thread-3] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
3. 2024-12-15T18:58:01.074+08:00 INFO 15392 --- [pool-2-thread-3] com.zaxxer.hikari.pool.HikariPool : HikariPool-1 - Added connection com.mysql.cj.jdbc.ConnectionImpl@9706daa
4. 2024-12-15T18:58:01.076+08:00 INFO 15392 --- [pool-2-thread-3] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
5. 1868249143658676227
6. 1868249143658676228
7. 1868249143658676226