如何在org.apache.ftpserver中允许匿名登录？

import org.apache.ftpserver.FtpServer;
import org.apache.ftpserver.FtpServerFactory;
import org.apache.ftpserver.ftplet.Authority;
import org.apache.ftpserver.ftplet.FtpException;
import org.apache.ftpserver.ftplet.UserManager;
import org.apache.ftpserver.listener.ListenerFactory;
import org.apache.ftpserver.usermanager.impl.BaseUser;
import org.apache.ftpserver.usermanager.impl.ConcurrentLoginPermission;
import org.apache.ftpserver.usermanager.impl.TransferRatePermission;
import org.apache.ftpserver.usermanager.impl.WritePermission;

public class AnonymousFtpServer {

    public static void main(String[] args) throws FtpException {
        // 创建FtpServer实例
        FtpServerFactory serverFactory = new FtpServerFactory();
        ListenerFactory listenerFactory = new ListenerFactory();

        // 配置匿名登录
        UserManager userManager = serverFactory.getUserManager();
        BaseUser anonymousUser = new BaseUser();
        anonymousUser.setName("anonymous");
        anonymousUser.setPassword("anonymous");
        anonymousUser.setEnabled(true);
        anonymousUser.setHomeDirectory("/path/to/your/ftp/root");

        // 设置权限
        ConcurrentLoginPermission concurrentLoginPermission = new ConcurrentLoginPermission(10, 10);
        WritePermission writePermission = new WritePermission(false);
        TransferRatePermission transferRatePermission = new TransferRatePermission(1024, 1024);
        Authority[] authorities = {concurrentLoginPermission, writePermission, transferRatePermission};
        anonymousUser.setAuthorities(authorities);

        // 添加匿名用户
        userManager.save(anonymousUser);

        // 设置监听器
        listenerFactory.setPort(21);
        serverFactory.addListener("default", listenerFactory.createListener());

        // 启动FtpServer
        FtpServer server = serverFactory.createServer();
        server.start();
    }
}