如何在Smack客户端中注册带内用户，特别是Ejabberd中的虚拟主机？

String serverAddress = "xmpp.example.com";
int serverPort = 5222;
String domain = "example.com";
XMPPTCPConnectionConfiguration config = XMPPTCPConnectionConfiguration.builder()
    .setHost(serverAddress)
    .setPort(serverPort)
    .setXmppDomain(domain)
    .build();
AbstractXMPPConnection connection = new XMPPTCPConnection(config);

connection.setDebuggerEnabled(true); // 启用调试模式，可查看通信详情
ReconnectionManager.getInstanceFor(connection).enableAutomaticReconnection(); // 启用自动重连

try {
    connection.connect();
} catch (SmackException | IOException | XMPPException e) {
    e.printStackTrace();
}

try {
    connection.login(username, password, resource);
} catch (SmackException | IOException | XMPPException e) {
    e.printStackTrace();
}

AccountManager accountManager = AccountManager.getInstance(connection);
try {
    accountManager.createAccount(username, password);
} catch (SmackException | InterruptedException | XMPPException.XMPPErrorException e) {
    e.printStackTrace();
}