java SpringBoot注解@Async不生效的解决方法

@Service
@EnableAsync
public class DemoService {
    public void add(){
        DemoService bean = SpringUtil.getBean(DemoService.class);
        System.out.println("开始");
        bean.sendToKafka();
        System.out.println("结束");
    }
    @Async
    public void sendToKafka() {
        try {
            Thread.sleep(10000);
            System.out.println("我睡醒了！！！");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

@Service
@EnableAsync
public class AsyncHandle {
    @Async
    public void sendToKafka() {
        try {
            Thread.sleep(10000);
            System.out.println("我睡醒了！！！");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

@Service
public class DemoService {
    @Autowired
    private AsyncHandle asyncHandle;
    
    public void add(){
        System.out.println("开始");
        asyncHandle.sendToKafka();
        System.out.println("结束");
    }
}