fix: shutdown thread pool before the container closes

spring-cloud-starter-tencent-polaris-discovery/src/main/java/com/tencent/cloud/polaris/discovery/refresh/PolarisRefreshApplicationReadyEventListener.java

@@ -25,14 +25,13 @@ import com.tencent.polaris.client.util.NamedThreadFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.springframework.beans.factory.DisposableBean;
 import org.springframework.boot.context.event.ApplicationReadyEvent;
 import org.springframework.cloud.client.discovery.event.HeartbeatEvent;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
 import org.springframework.context.ApplicationListener;
 
-import javax.annotation.PreDestroy;
-
 import static com.tencent.cloud.polaris.discovery.refresh.PolarisServiceStatusChangeListener.INDEX;
 
 /**
@@ -40,7 +39,7 @@ import static com.tencent.cloud.polaris.discovery.refresh.PolarisServiceStatusCh
  *
  * @author Haotian Zhang
  */
-public class PolarisRefreshApplicationReadyEventListener implements ApplicationListener<ApplicationReadyEvent>, ApplicationEventPublisherAware {
+public class PolarisRefreshApplicationReadyEventListener implements ApplicationListener<ApplicationReadyEvent>, ApplicationEventPublisherAware, DisposableBean {
 
 	private static final Logger LOG = LoggerFactory.getLogger(PolarisRefreshApplicationReadyEventListener.class);
 	private static final int DELAY = 60;
@@ -86,8 +85,8 @@ public class PolarisRefreshApplicationReadyEventListener implements ApplicationL
 		this.publisher = applicationEventPublisher;
 	}
 
-	@PreDestroy
-	public void destroy() {
+	@Override
+	public void destroy() throws Exception {
 		refreshExecutor.shutdown();
 	}
 }