Graceful shutdown enhancement in Spring (#2901)

Author: LiZhenNet

dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/DubboShutdownHook.java

@@ -55,13 +55,13 @@ public void run() {
         if (logger.isInfoEnabled()) {
             logger.info("Run shutdown hook now.");
         }
-        destroyAll();
+        doDestroy();
     }
 
     /**
      * Destroy all the resources, including registries and protocols.
      */
-    public void destroyAll() {
+    public void doDestroy() {
         if (!destroyed.compareAndSet(false, true)) {
             return;
         }

dubbo-config/dubbo-config-spring/src/main/java/org/apache/dubbo/config/spring/extension/SpringExtensionFactory.java

@@ -44,6 +44,7 @@ public class SpringExtensionFactory implements ExtensionFactory {
 
     public static void addApplicationContext(ApplicationContext context) {
         contexts.add(context);
+        Runtime.getRuntime().removeShutdownHook(DubboShutdownHook.getDubboShutdownHook());
         BeanFactoryUtils.addApplicationListener(context, shutdownHookListener);
     }
 
@@ -105,11 +106,8 @@ private static class ShutdownHookListener implements ApplicationListener {
         @Override
         public void onApplicationEvent(ApplicationEvent event) {
             if (event instanceof ContextClosedEvent) {
-                // we call it anyway since dubbo shutdown hook make sure its destroyAll() is re-entrant.
-                // pls. note we should not remove dubbo shutdown hook when spring framework is present, this is because
-                // its shutdown hook may not be installed.
                 DubboShutdownHook shutdownHook = DubboShutdownHook.getDubboShutdownHook();
-                shutdownHook.destroyAll();
+                shutdownHook.doDestroy();
             }
         }
     }