fix(nacos): fix issue #859

spring-cloud-alibaba-examples/nacos-example/nacos-config-example/src/main/java/com/alibaba/cloud/examples/Application.java

@@ -88,10 +88,17 @@ class SampleController {
 	String userName;
 
 	@Value("${user.age:25}")
-	int age;
+	Integer age;
+
+	private final NacosConfigManager nacosConfigManager;
+
+	public SampleController(NacosConfigManager nacosConfigManager) {
+		this.nacosConfigManager = nacosConfigManager;
+	}
 
 	@RequestMapping("/user")
 	public String simple() {
-		return "Hello Nacos Config!" + "Hello " + userName + " " + age + "!";
+		return "Hello Nacos Config!" + "Hello " + userName + " " + age + "!"
+				+ nacosConfigManager.getConfigService();
 	}
 }

spring-cloud-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/NacosConfigManager.java

@@ -26,10 +26,8 @@ import org.springframework.context.ApplicationContextAware;
  */
 public class NacosConfigManager implements ApplicationContextAware {
 
-	private ConfigService configService;
-
 	public ConfigService getConfigService() {
-		return configService;
+		return ServiceHolder.getInstance().getService();
 	}
 
 	@Override
@@ -37,6 +35,34 @@ public class NacosConfigManager implements ApplicationContextAware {
 			throws BeansException {
 		NacosConfigProperties properties = applicationContext
 				.getBean(NacosConfigProperties.class);
-		configService = properties.configServiceInstance();
+		ServiceHolder holder = ServiceHolder.getInstance();
+		if (!holder.alreadyInit) {
+			ServiceHolder.getInstance().setService(properties.configServiceInstance());
+		}
 	}
+
+	static class ServiceHolder {
+		private ConfigService service = null;
+
+		private boolean alreadyInit = false;
+
+		private static final ServiceHolder holder = new ServiceHolder();
+
+		ServiceHolder() {
+		}
+
+		static ServiceHolder getInstance() {
+			return holder;
+		}
+
+		void setService(ConfigService service) {
+			alreadyInit = true;
+			this.service = service;
+		}
+
+		ConfigService getService() {
+			return service;
+		}
+	}
+
 }

spring-cloud-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/NacosNamingManager.java

@@ -27,15 +27,12 @@ import org.springframework.context.ApplicationContextAware;
  */
 public class NacosNamingManager implements ApplicationContextAware {
 
-	private NamingService namingService;
-	private NamingMaintainService namingMaintainService;
-
 	public NamingService getNamingService() {
-		return namingService;
+		return ServiceHolder.getInstance().getNamingService();
 	}
 
 	public NamingMaintainService getNamingMaintainService() {
-		return namingMaintainService;
+		return ServiceHolder.getInstance().getNamingMaintainService();
 	}
 
 	@Override
@@ -43,7 +40,46 @@ public class NacosNamingManager implements ApplicationContextAware {
 			throws BeansException {
 		NacosDiscoveryProperties properties = applicationContext
 				.getBean(NacosDiscoveryProperties.class);
-		namingService = properties.namingServiceInstance();
+		ServiceHolder holder = ServiceHolder.getInstance();
-		namingMaintainService = properties.namingMaintainServiceInstance();
+		if (!holder.alreadyInit[0]) {
+			holder.setNamingService(properties.namingServiceInstance());
+		}
+		if (!holder.alreadyInit[1]) {
+			holder.setNamingMaintainService(properties.namingMaintainServiceInstance());
+		}
+	}
+
+	static class ServiceHolder {
+		private NamingService namingService = null;
+		private NamingMaintainService namingMaintainService = null;
+
+		final boolean[] alreadyInit = new boolean[2];
+
+		private static final ServiceHolder HOLDER = new ServiceHolder();
+
+		ServiceHolder() {
+		}
+
+		static ServiceHolder getInstance() {
+			return HOLDER;
+		}
+
+		public NamingService getNamingService() {
+			return namingService;
+		}
+
+		void setNamingService(NamingService namingService) {
+			alreadyInit[0] = true;
+			this.namingService = namingService;
+		}
+
+		NamingMaintainService getNamingMaintainService() {
+			return namingMaintainService;
+		}
+
+		void setNamingMaintainService(NamingMaintainService namingMaintainService) {
+			alreadyInit[1] = true;
+			this.namingMaintainService = namingMaintainService;
+		}
 	}
 }