// fromTime 原始时区 // toTime 需要转换到的时区  public static Date getGMTTime(Date retdate, String fromTime, String toTime){   Calendar cal = Calendar.getInstance();  cal.setTimeZone(TimeZone.getTimeZone(toTime));  cal.setTime(retdate);  Calendar date = Calendar.getInstance();  date.setTimeZone(TimeZone.getTimeZone(fromTime));  date.set(Calendar.MILLISECOND, cal.get(Calendar.MILLISECOND));   date.set(cal.get(Calendar.YEAR),cal.get(Calendar.MONTH),cal.get(Calendar.DAY_OF_MONTH),cal.get(Calendar.HOUR_OF_DAY),cal.get(Calendar.MINUTE),cal.get(Calendar.SECOND));  return date.getTime(); }