要使自定义Executor正常工作，请确保将其注册为Bean，并在使用@Async注解的方法上引用它：

@Bean(name = "transcodingPoolTaskExecutor")
public Executor transcodingPoolTaskExecutor() {
    final ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
    executor.setCorePoolSize(2);
    executor.setMaxPoolSize(2);
    executor.setQueueCapacity(500);
    executor.setThreadNamePrefix("transcoder-");
    executor.initialize();
    return executor;
}

而在@Service里面是拿着这个方法的：

@Async("transcodingPoolTaskExecutor")
public void transcodeVideo(UUID fileId) {
    mediaFileService.transcodeVideo(fileId);
}

您也可以通过创建一个实现AsyncConfigurer的Configuration类来重新定义默认执行器。

@EnableAsync
@Configuration
public class AsyncConfig implements AsyncConfigurer {
    @Value("${async.executor.corePoolSize:20}")
    private int corePoolSize;

    @Value("${async.executor.maxPoolSize:100}")
    private int maxPoolSize;

    @Value("${async.executor.queueCapacity:50}")
    private int queueCapacity;

    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(corePoolSize);
        executor.setMaxPoolSize(maxPoolSize);
        executor.setQueueCapacity(queueCapacity);
        executor.setThreadNamePrefix("Async Executor -");
        executor.initialize();
        return executor;
    }
}

在这种情况下，您不需要在@Async注解中指定执行器名称，Spring将使用您在AsyncConfig中定义的执行器。
它与ygoldt提供的解决方案非常相似，但在这种情况下，您不需要在每个@Async注解中指定执行者的名称，因此它消除了执行者名称中潜在的拼写错误。