Merge pull request #1724 from yuhuangbin/master

[Enhancement] NacosDiscoveryClient always getNamingservice from Nacosmanager

spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/discovery/NacosServiceDiscovery.java

@@ -38,13 +38,12 @@ public class NacosServiceDiscovery {
 
 	private NacosDiscoveryProperties discoveryProperties;
 
-	private NamingService namingService;
+	private NacosServiceManager nacosServiceManager;
 
 	public NacosServiceDiscovery(NacosDiscoveryProperties discoveryProperties,
 			NacosServiceManager nacosServiceManager) {
 		this.discoveryProperties = discoveryProperties;
-		this.namingService = nacosServiceManager
-				.getNamingService(discoveryProperties.getNacosProperties());
+		this.nacosServiceManager = nacosServiceManager;
 	}
 
 	/**
@@ -55,7 +54,7 @@ public class NacosServiceDiscovery {
 	 */
 	public List<ServiceInstance> getInstances(String serviceId) throws NacosException {
 		String group = discoveryProperties.getGroup();
-		List<Instance> instances = namingService.selectInstances(serviceId, group, true);
+		List<Instance> instances = namingService().selectInstances(serviceId, group, true);
 		return hostToServiceInstanceList(instances, serviceId);
 	}
 
@@ -66,7 +65,7 @@ public class NacosServiceDiscovery {
 	 */
 	public List<String> getServices() throws NacosException {
 		String group = discoveryProperties.getGroup();
-		ListView<String> services = namingService.getServicesOfServer(1,
+		ListView<String> services = namingService().getServicesOfServer(1,
 				Integer.MAX_VALUE, group);
 		return services.getData();
 	}
@@ -111,4 +110,8 @@ public class NacosServiceDiscovery {
 		return nacosServiceInstance;
 	}
 
+	private NamingService namingService() {
+		return nacosServiceManager.getNamingService(discoveryProperties.getNacosProperties());
+	}
+
 }