Java中判断两个Date对象是不是同一天

1. Calendar

Calendar cal1 = Calendar.getInstance();
Calendar cal2 = Calendar.getInstance();
cal1.setTime(date1);
cal2.setTime(date2);
boolean sameDay = cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                    cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR);

2. org.apache.commons.lang.time.DateUtils

boolean samedate = DateUtils.isSameDay(date1, date2); 

3. SimpleDateFormat

SimpleDateFormat fmt = new SimpleDateFormat("yyyyMMdd");
fmt.format(date1).equals(fmt.format(date2));