### Environment

* Dubbo version: 2.7.6-SNAPSHOT
* Operating System version: Mac
* Java version: 1.8

### Steps to reproduce this issue

run dubbo-samples-simplified-registry-xml 

org.apache.dubbo.samples.simplified.registry.xml.DemoServiceIT
### Expected Result

should pass

### Actual Result

throw exception
import static org.apache.dubbo.common.constants.CommonConstants.ANY_VALUE;
import static org.apache.dubbo.common.constants.CommonConstants.DISABLED_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.DUBBO_PROTOCOL;
import static org.apache.dubbo.common.constants.CommonConstants.ENABLED_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.GROUP_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.INTERFACE_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.MONITOR_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.PROTOCOL_KEY;
import static org.apache.dubbo.common.constants.RegistryConstants.APP_DYNAMIC_CONFIGURATORS_CATEGORY;
import static org.apache.dubbo.common.constants.RegistryConstants.CATEGORY_KEY;
import static org.apache.dubbo.common.constants.RegistryConstants.COMPATIBLE_CONFIG_KEY;
import static org.apache.dubbo.common.constants.RegistryConstants.CONFIGURATORS_CATEGORY;
import static org.apache.dubbo.common.constants.RegistryConstants.CONSUMERS_CATEGORY;
import static org.apache.dubbo.common.constants.RegistryConstants.DEFAULT_CATEGORY;
import static org.apache.dubbo.common.constants.RegistryConstants.DYNAMIC_CONFIGURATORS_CATEGORY;
import static org.apache.dubbo.common.constants.RegistryConstants.EMPTY_PROTOCOL;
import static org.apache.dubbo.common.constants.RegistryConstants.PROVIDERS_CATEGORY;
import static org.apache.dubbo.common.constants.RegistryConstants.ROUTERS_CATEGORY;
import static org.apache.dubbo.common.constants.RegistryConstants.ROUTE_PROTOCOL;
import static org.apache.dubbo.registry.Constants.CONFIGURATORS_SUFFIX;
import static org.apache.dubbo.registry.Constants.REGISTER_KEY;
import static org.apache.dubbo.registry.Constants.SIMPLIFIED_KEY;
import static org.apache.dubbo.registry.integration.RegistryProtocol.DEFAULT_REGISTER_CONSUMER_KEYS;
import static org.apache.dubbo.remoting.Constants.CHECK_KEY;
import static org.apache.dubbo.rpc.cluster.Constants.REFER_KEY;
import static org.apache.dubbo.rpc.cluster.Constants.ROUTER_KEY;
/**
 * RegistryDirectory
 */
public class RegistryDirectory<T> extends AbstractDirectory<T> implements NotifyListener {