Dubbo Version: 3.0.10
注册失败，unexport时，subscribeUrl和registerUrl此时为空，需要判断空处理。 
<img width="944" alt="image" src="https://user-images.githubusercontent.com/12670328/200469537-41a4ccb5-adda-4231-9f71-9af9fec2172d.png">


* limitations under the License.
 */
package org.apache.dubbo.registry.integration;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.config.ConfigurationUtils;
import org.apache.dubbo.common.config.configcenter.DynamicConfiguration;
import org.apache.dubbo.common.logger.ErrorTypeAwareLogger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.threadpool.manager.FrameworkExecutorRepository;
import org.apache.dubbo.common.timer.HashedWheelTimer;
import org.apache.dubbo.common.url.component.ServiceConfigURL;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.NamedThreadFactory;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.common.utils.UrlUtils;
import org.apache.dubbo.registry.NotifyListener;
import org.apache.dubbo.registry.Registry;
import org.apache.dubbo.registry.RegistryFactory;
import org.apache.dubbo.registry.RegistryService;
import org.apache.dubbo.registry.client.ServiceDiscoveryRegistryDirectory;
import org.apache.dubbo.registry.client.migration.MigrationClusterInvoker;
import org.apache.dubbo.registry.client.migration.ServiceDiscoveryMigrationInvoker;
import org.apache.dubbo.registry.retry.ReExportTask;
import org.apache.dubbo.registry.support.SkipFailbackWrapperException;
import org.apache.dubbo.rpc.Exporter;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.Protocol;
import org.apache.dubbo.rpc.ProtocolServer;
import org.apache.dubbo.rpc.ProxyFactory;
import org.apache.dubbo.rpc.RpcException;