https://github.com/apache/incubator-dubbo/blob/04c93e8b98250230c4d22423372acd1c29e2c770/dubbo-remoting/dubbo-remoting-zookeeper/src/main/java/com/alibaba/dubbo/remoting/zookeeper/curator/CuratorZookeeperClient.java#L49

rt
import org.apache.dubbo.remoting.zookeeper.ChildListener;
import org.apache.dubbo.remoting.zookeeper.StateListener;
import org.apache.dubbo.remoting.zookeeper.support.AbstractZookeeperClient;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.api.CuratorWatcher;
import org.apache.curator.framework.state.ConnectionState;
import org.apache.curator.framework.state.ConnectionStateListener;
import org.apache.curator.retry.RetryNTimes;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException.NoNodeException;
import org.apache.zookeeper.KeeperException.NodeExistsException;
import org.apache.zookeeper.WatchedEvent;
import java.util.Collections;
import java.util.List;
public class CuratorZookeeperClient extends AbstractZookeeperClient<CuratorWatcher> {
    private final CuratorFramework client;
    public CuratorZookeeperClient(URL url) {
        super(url);
        try {
            CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder()
                    .connectString(url.getBackupAddress())
                    .retryPolicy(new RetryNTimes(1, 1000))
                    .connectionTimeoutMs(5000);
            String authority = url.getAuthority();
            if (authority != null && authority.length() > 0) {
                builder = builder.authorization("digest", authority.getBytes());
            }
            client = builder.build();
            client.getConnectionStateListenable().addListener(new ConnectionStateListener() {