【spring-boot】如何优雅关闭服务

@Slf4j
public class GracefulShutdownConfiguration {

    @Bean
    public GracefulShutdown gracefulShutdown() {
        return new GracefulShutdown();
    }

    @Bean
    public TomcatEmbeddedServletContainerFactory webServerFactory(final GracefulShutdown gracefulShutdown) {
        TomcatEmbeddedServletContainerFactory factory = new TomcatEmbeddedServletContainerFactory();
        factory.addConnectorCustomizers(gracefulShutdown);
        return factory;
    }

    class GracefulShutdown implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {

        private volatile Connector connector;

        @Override
        public void customize(Connector connector) {
            this.connector = connector;
        }

        @Override
        public void onApplicationEvent(ContextClosedEvent event) {
            log.info("signal: shutdown");
            log.info(event.toString());
            this.connector.pause();
            Executor executor = this.connector.getProtocolHandler().getExecutor();
            if (executor instanceof ThreadPoolExecutor) {
                try {
                    ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
                    threadPoolExecutor.shutdown();
                    log.info(threadPoolExecutor.getActiveCount() + "");
                    if (!threadPoolExecutor.awaitTermination(30, TimeUnit.SECONDS)) {
                        log.warn("Tomcat thread pool did not shut down gracefully within "
                            + "30 seconds. Proceeding with forceful shutdown");
                    }

                } catch (InterruptedException ex) {
                    Thread.currentThread().interrupt();
                }

            }
        }
    }
}