如何用 Java 从 Internet 时间服务器检索格林威治标准时间 (GMT)？

import java.net.InetAddress;
import java.util.Date;

import org.apache.commons.net.ntp.NTPUDPClient;
import org.apache.commons.net.ntp.TimeInfo;
import org.apache.commons.net.ntp.TimeStamp;

public class TimeServer {

    public static void main(String[] args) throws Exception {
        // Define the time server address
        String TIME_SERVER = "in.pool.ntp.org"; 

        // Instantiate a NTP client
        NTPUDPClient timeClient = new NTPUDPClient();

        // Get the IP address of the time server
        InetAddress inetAddress = InetAddress.getByName(TIME_SERVER);

        // Retrieve time information from the server
        TimeInfo timeInfo = timeClient.getTime(inetAddress);

        // Extract the transmission timestamp from the received packet
        long returnTime = timeInfo.getMessage().getTransmitTimeStamp().getTime();

        // Convert the timestamp to a Date object for readability
        Date time = new Date(returnTime);

        // Display the obtained GMT
        System.out.println("Current GMT: " + time);
    }
}