### 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
}
                }
                if (!accept) {
                    continue;
                }
            }
            if (EMPTY_PROTOCOL.equals(providerUrl.getProtocol())) {
                continue;
            }
            if (!ExtensionLoader.getExtensionLoader(Protocol.class).hasExtension(providerUrl.getProtocol())) {
                logger.error(new IllegalStateException("Unsupported protocol " + providerUrl.getProtocol() +
                        " in notified url: " + providerUrl + " from registry " + getUrl().getAddress() +
                        " to consumer " + NetUtils.getLocalHost() + ", supported protocol: " +
                        ExtensionLoader.getExtensionLoader(Protocol.class).getSupportedExtensions()));
                continue;
            }
            URL url = mergeUrl(providerUrl);
            String key = url.toFullString(); 
            if (keys.contains(key)) { 
                continue;
            }
            keys.add(key);
            
            Map<String, Invoker<T>> localUrlInvokerMap = this.urlInvokerMap; 
            Invoker<T> invoker = localUrlInvokerMap == null ? null : localUrlInvokerMap.get(key);
            if (invoker == null) { 
                try {
                    boolean enabled = true;
                    if (url.hasParameter(DISABLED_KEY)) {
                        enabled = !url.getParameter(DISABLED_KEY, false);