本文实例讲述了Java判断两个日期相差天数的方法。分享给大家供大家参考。具体如下：
import java.util.Calendar;public class DateDifferent{ public static void main(String[] args){ Calendar calendar1 = Calendar.getInstance(); Calendar calendar2 = Calendar.getInstance(); calendar1.set(2007, 01, 10); calendar2.set(2007, 07, 01); long milliseconds1 = calendar1.getTimeInMillis(); long milliseconds2 = calendar2.getTimeInMillis(); long diff = milliseconds2 - milliseconds1; long diffSeconds = diff / 1000; long diffMinutes = diff / (60 * 1000); long diffHours = diff / (60 * 60 * 1000); long diffDays = diff / (24 * 60 * 60 * 1000); System.out.println("/nThe Date Different Example"); System.out.println("Time in milliseconds: " + diff + " milliseconds."); System.out.println("Time in seconds: " + diffSeconds + " seconds."); System.out.println("Time in minutes: " + diffMinutes + " minutes."); System.out.println("Time in hours: " + diffHours + " hours."); System.out.println("Time in days: " + diffDays + " days."); }}把上面的代码放在项目里使用了一下，【求日期部分】是要满24小时才算一天的，不太适应项目的需求，故改成这样子。
/** * 得到两个日期相差的天数 */public static int getBetweenDay(Date date1, Date date2) { Calendar d1 = new GregorianCalendar(); d1.setTime(date1); Calendar d2 = new GregorianCalendar(); d2.setTime(date2); int days = d2.get(Calendar.DAY_OF_YEAR)- d1.get(Calendar.DAY_OF_YEAR); System.out.println("days="+days); int y2 = d2.get(Calendar.YEAR); if (d1.get(Calendar.YEAR) != y2) {// d1 = (Calendar) d1.clone(); do { days += d1.getActualMaximum(Calendar.DAY_OF_YEAR); d1.add(Calendar.YEAR, 1); } while (d1.get(Calendar.YEAR) != y2); } return days;}希望本文所述对大家的java程序设计有所帮助。