如何以字符串形式获取XMPP服务域Smack 4

import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.SmackException;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.tcp.XMPPTCPConnection;

public class XMPPServiceDomainExample {
    public static void main(String[] args) {
        // 创建XMPP连接配置
        ConnectionConfiguration config = new ConnectionConfiguration("xmpp.example.com", 5222);

        // 创建XMPP连接
        XMPPConnection connection = new XMPPTCPConnection(config);

        try {
            // 连接到XMPP服务器
            connection.connect();

            // 获取XMPP服务域
            String serviceDomain = connection.getServiceName();
            System.out.println("XMPP服务域：" + serviceDomain);
        } catch (SmackException | XMPPException | InterruptedException e) {
            e.printStackTrace();
        } finally {
            // 断开与XMPP服务器的连接
            connection.disconnect();
        }
    }
}