如果你想避免解析日期，只是想要一个GMT的时间戳，你可以使用:

final Date gmt = new Timestamp(System.currentTimeMillis()
            - Calendar.getInstance().getTimeZone()
                    .getOffset(System.currentTimeMillis()));

这肯定会返回UTC时间:作为字符串和日期对象!

static final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";

public static Date getUTCdatetimeAsDate() {
    // note: doesn't check for null
    return stringDateToDate(getUTCdatetimeAsString());
}

public static String getUTCdatetimeAsString() {
    final SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT);
    sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
    final String utcTime = sdf.format(new Date());

    return utcTime;
}

public static Date stringDateToDate(String StrDate) {
    Date dateToReturn = null;
    SimpleDateFormat dateFormat = new SimpleDateFormat(DATEFORMAT);

    try {
        dateToReturn = (Date)dateFormat.parse(StrDate);
    }
    catch (ParseException e) {
        e.printStackTrace();
    }

    return dateToReturn;
}

这里还有一个获取GMT时间戳对象的建议:

import java.sql.Timestamp;
import java.util.Calendar;

...

private static Timestamp getGMT() {
   Calendar cal = Calendar.getInstance();
   return new Timestamp(cal.getTimeInMillis()
                       -cal.get(Calendar.ZONE_OFFSET)
                       -cal.get(Calendar.DST_OFFSET));
}

转换UTC当前日期时间:

DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");

DateTimeZone dateTimeZone = DateTimeZone.getDefault(); //Default Time Zone

DateTime currDateTime = new DateTime(); //Current DateTime

long utcTime = dateTimeZone.convertLocalToUTC(currDateTime .getMillis(), false);

String currTime = formatter.print(utcTime); //UTC time converted to string from long in format of formatter

currDateTime = formatter.parseDateTime(currTime); //Converted to DateTime in UTC

为了简单起见，你可以使用Calendar来创建一个UTC Date:

Calendar.getInstance(TimeZone.getTimeZone("UTC"));

它将使用“UTC”时区为Calendar构造一个新实例。

如果需要该日历中的Date对象，可以使用getTime()。

日历aGMTCalendar = Calendar. getinstance (TimeZone.getTimeZone("GMT")); 然后，使用aGMTCalendar对象执行的所有操作都将使用GMT时区完成，并且不会应用夏令时或固定偏移量

错了!

Calendar aGMTCalendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
aGMTCalendar.getTime(); //or getTimeInMillis()

and

Calendar aNotGMTCalendar = Calendar.getInstance(TimeZone.getTimeZone("GMT-2"));aNotGMTCalendar.getTime();

会在同一时间回来。同上的对

new Date(); //it's not GMT.