Java日历获取当前日期，不带小时、分钟、秒和毫秒，以毫秒为单位

I would like to get the current date in milliseconds with only year, month and date. But when I use this code:

Calendar cal = Calendar.getInstance();
cal.clear(Calendar.HOUR);
cal.clear(Calendar.MINUTE);
cal.clear(Calendar.SECOND);
cal.clear(Calendar.MILLISECOND);
currentDate = cal.getTimeInMillis();

我仍然以毫秒为单位获得时间.我该如何解决这个问题?

Calendar cal = Calendar.getInstance();
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
currentDate = cal.getTimeInMillis();