Yesterday or Tomorrow

Thinking about days and nights and the good old Java 'when are we now?' classes Date and Calendar. If I want to know if something is earlier than today...

public boolean isBeforeToday(Date date) {
  Calendar cal = Calendar.getInstance();
  cal.set(Calendar.HOUR, 0);
  cal.set(Calendar.MINUTE, 0);
  cal.set(Calendar.SECOND, 0);
  cal.set(Calendar.MILLISECOND, 0);

  Date startOfToday = cal.getTime();
  return date.before(startOfToday);
}

It feels pretty clunky. Likewise for after today...

public boolean isAfterToday(Date date) {
   Calendar cal = Calendar.getInstance();
   cal.set(Calendar.HOUR, 23);
   cal.set(Calendar.MINUTE, 59);
   cal.set(Calendar.SECOND, 59);
   cal.set(Calendar.MILLISECOND, 999);

   Date endOfToday = cal.getTime();
   return date.after(endOfToday);
}

What if I want to know if a date is within the day before today (otherwise known as yesterday)...

public boolean isYesterday(Date date) {
   // get a calendar for yesterday
   Calendar yesterday = Calendar.getInstance();
   yesterday.add(Calendar.DAY_OF_YEAR, -1);

   // and one for the test date
   Calendar cal = Calendar.getInstance();
   cal.setTime(date);

   // true if year and day of year are equal to yesterday
   return (yesterday.get(Calendar.YEAR) == cal.get(Calendar.YEAR))
     && (yesterday.get(Calendar.DAY_OF_YEAR) == cal
     .get(Calendar.DAY_OF_YEAR));
}

Long winded? So I got to thinking about some possible short cuts and wondered what the following could give us...

public long getOrdinalDayForDate(Date date) {
  final long MILLISECS_IN_DAY = 1000 * 60 * 60 * 24;
  return date.getTime() / MILLISECS_IN_DAY;
}

By giving each date an index, day number from the first day of 1970, we can have...

public boolean isToday(Date date) {
  return getOrdinalDayForDate(date) == getOrdinalDayForDate(new Date());
}
    
public boolean isYesterday(Date date) {
  return getOrdinalDayForDate(date) == (getOrdinalDayForDate(new Date())-1);
}
    
public boolean isTomorrow(Date date) {
  return getOrdinalDayForDate(date) == (getOrdinalDayForDate(new Date())+1);
}

Am I on the right track with this?