在測試工作中經常會使用到比較兩個日期相差的天數，我之前用過實現這一功能的兩個版本的方法，原始碼如下：

版本一：

public static int getIntervalDays(Date fDate, Date oDate) {
       if (null == fDate || null == oDate) {
           return -1;
       }
       long intervalMilli = oDate.getTime() - fDate.getTime();
       return (int) (intervalMilli / (24 * 60 * 60 * 1000));
    }
 

public static int daysOfTwo(Date fDate, Date oDate) {
       Calendar aCalendar = Calendar.getInstance();
       aCalendar.setTime(fDate);
       int day1 = aCalendar.get(Calendar.DAY_OF_YEAR);
       aCalendar.setTime(oDate);
       int day2 = aCalendar.get(Calendar.DAY_OF_YEAR);
       return day2 - day1;
    }
 

public static void main(String[] args) {
       Date fDate = new GregorianCalendar().getTime();
       Date oDate = new GregorianCalendar(2009, 2, 15,13,13,0).getTime();
       System.out.println("使用 getIntervalDays 相差天數 = "
                     + getIntervalDays(fDate, oDate));
       System.out.println("使用 daysOfTwo 相差天數 = "
              + daysOfTwo(fDate, oDate));
}
 

轉載自：http://blog.csdn.net/shiyuezhong/article/details/9196803