support zone empty string

spring-cloud-starter-tencent-polaris-discovery/src/main/java/com/tencent/cloud/polaris/registry/PolarisServiceRegistry.java

@@ -113,6 +113,7 @@ public class PolarisServiceRegistry implements ServiceRegistry<PolarisRegistrati
 		}
 		registration.customize();
 		MetadataContext.setLocalService(serviceId);
+		MetadataContext.setLocalNamespace(polarisDiscoveryProperties.getNamespace());
 
 		// Register instance.
 		InstanceRegisterRequest instanceRegisterRequest = new InstanceRegisterRequest();

spring-cloud-tencent-commons/src/main/java/com/tencent/cloud/common/metadata/MetadataContext.java

@@ -133,6 +133,10 @@ public class MetadataContext extends com.tencent.polaris.metadata.core.manager.M
 		LOCAL_SERVICE = service;
 	}
 
+	public static void setLocalNamespace(String namespace) {
+		LOCAL_NAMESPACE = namespace;
+	}
+
 	private Map<String, String> getMetadataAsMap(MetadataType metadataType, TransitiveType transitiveType, boolean caller) {
 		MetadataContainer metadataContainer = getMetadataContainer(metadataType, caller);
 		Map<String, String> values = new HashMap<>();

spring-cloud-tencent-polaris-context/src/main/java/com/tencent/cloud/polaris/context/PostInitPolarisSDKContext.java

@@ -40,7 +40,7 @@ public class PostInitPolarisSDKContext {
 		if (StringUtils.isNotBlank(region)) {
 			valueContext.setValue(RoutingProto.NearbyRoutingConfig.LocationLevel.REGION.name(), region);
 		}
-		if (StringUtils.isNotBlank(zone)) {
+		if (zone != null) {
 			valueContext.setValue(RoutingProto.NearbyRoutingConfig.LocationLevel.ZONE.name(), zone);
 		}
 		if (StringUtils.isNotBlank(campus)) {

spring-cloud-tencent-polaris-context/src/main/java/com/tencent/cloud/polaris/context/config/PolarisContextEnvironmentPostProcessor.java

@@ -96,7 +96,7 @@ public final class PolarisContextEnvironmentPostProcessor implements Environment
 
 		// zone
 		String zone = environment.getProperty("tsf_zone");
-		if (StringUtils.isNotBlank(zone)) {
+		if (zone != null) {
 			polarisEnvProperties.put("spring.cloud.tencent.metadata.content.zone", zone);
 		}
 

spring-cloud-tencent-polaris-context/src/main/java/com/tencent/cloud/polaris/context/config/extend/tsf/TsfInstanceMetadataProvider.java

@@ -68,7 +68,7 @@ public class TsfInstanceMetadataProvider implements InstanceMetadataProvider {
 			tsfMetadata.put(TsfMetadataConstants.TSF_REGION, tsfCoreProperties.getTsfRegion());
 		}
 
-		if (StringUtils.isNotBlank(tsfCoreProperties.getTsfZone())) {
+		if (tsfCoreProperties.getTsfZone() != null) {
 			tsfMetadata.put(TsfMetadataConstants.TSF_ZONE, tsfCoreProperties.getTsfZone());
 		}