为DCL中使用的变量添加volatile特性。

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

@@ -43,9 +43,9 @@ public class NacosServiceManager {
 
 	private NacosDiscoveryProperties nacosDiscoveryPropertiesCache;
 
-	private NamingService namingService;
+	private volatile NamingService namingService;
 
-	private NamingMaintainService namingMaintainService;
+	private volatile NamingMaintainService namingMaintainService;
 
 	public NamingService getNamingService(Properties properties) {
 		if (Objects.isNull(this.namingService)) {