1

在咨询了几个论坛后，我最终使用下面的代码来找到天差。但是，我发现逻辑有问题（可能是我的过目不忘？）。我看到 11 到 14 天和 11 到 15 天之间的差异是相同的。这怎么可能？

Date createdDate = new Date((2013 + 1900), (1 + 1), 11);
Date expirationDate = new Date((2013 + 1900), (1 + 1), 11);
for (int i = 11; i < 20; i++) {
    expirationDate.setDate(i);

    System.out.println("11 to " + i + " = "
            + (int) (expirationDate.getTime() - createdDate.getTime())
            / (1000 * 60 * 60 * 24));
}

输出是：

11 to 11 = 0
11 to 12 = 1
11 to 13 = 2
11 to 14 = 3
11 to 15 = 3
11 to 16 = 4
11 to 17 = 5
11 to 18 = 6
11 to 19 = 7
4

5 回答 5

4

使用Joda Time的Days#daysBetween(). 没有更好的办法。

DateMidnight createdDate = new DateMidnight(2013, 2, 11);

for (int i = 11; i < 20; i++) {

    DateMidnight expirationDate = new DateMidnight(2013, 2, i);
    int dayDifference = Days.daysBetween(createdDate, expirationDate);

    System.out.println("11 to " + i + " = " + dayDifference);
}
于 2013-01-11T00:11:56.050 回答
1

1000 * 60 * 60 * 24找到日差的方法是错误的。您可以使用JodaTime，但有一个纯 Java 解决方案。

让我们有两个初始化变量

Calendar firstDay = ...;
Calendar secondDay = ...;

和

firstDay.before(lastDay)

是true。

跑

int firstDayNo = firstDay.get(Calendar.DAY_OF_YEAR);
int secondDayNo = secondDay.get(Calendar.DAY_OF_YEAR);
int dayDifference, yearMultiplier;

dayDifference = -firstDayNo;
yearMultiplier = secondDay.get(Calendar.YEAR) - firstDay.get(Calendar.YEAR);
while (yearMultiplier > 0) {
    dayDifference += firstDay.getActualMaximum(Calendar.DAY_OF_YEAR);
    firstDay.add(Calendar.YEAR, 1);
    yearMultiplier--;
}
dayDifference += secondDayNo;

return dayDifference;
于 2015-01-13T17:03:23.260 回答
1

Date(year,day, month)构造函数已弃用。我会简单地使用日历方法来获得两天之间的差异：

Calendar cal1=Calendar.getInstance();
Calendar cal2=Calendar.getInstance();
cal1.setTime(createdDate);
cal2.setTime(expirationDate);
System.out.println(cal2.get(Calendar.DAY_OF_MONTH )-cal1.get(Calendar.DAY_OF_MONTH ) );

编辑：

Calendar cal1 = Calendar.getInstance();
cal1.set(2013, 2, 11);
Calendar cal2 = Calendar.getInstance();
cal2.set(2013, 2, 11);
for (int i = 11; i < 20; i++) {
 cal2.set(Calendar.DATE, i);
    System.out.println("11 to " + i + " = " + (cal2.get(Calendar.DAY_OF_MONTH) -cal1.get(Calendar.DAY_OF_MONTH)));
}

输出：

11 to 11 = 0
11 to 12 = 1
11 to 13 = 2
11 to 14 = 3
11 to 15 = 4
11 to 16 = 5
11 to 17 = 6
11 to 18 = 7
11 to 19 = 8
于 2013-01-11T00:04:24.463 回答
0

至少在当前版本中，您的代码会打印正确的结果

11 to 11 = 0
11 to 12 = 1
11 to 13 = 2
11 to 14 = 3
11 to 15 = 4
11 to 16 = 5
11 to 17 = 6
11 to 18 = 7
11 to 19 = 8

然而new Date((2013 + 1900), (1 + 1), 11);是不正确的，事实上它是5813-03-01。应该new Date((2013 - 1900), (1 - 1), 11);看到 Date(int year, int month, int day) API

Parameters:
year - the year minus 1900.
month - the month between 0-11.
date - the day of the month between 1-31.
于 2013-01-11T01:48:16.533 回答
0

使用浮动，我看到了问题。使用时间戳似乎不是查找两个日期之间天数差异的好方法。

11 到 11 = 0.0
11 到 12 = 1.0
11 到 13 = 2.0
11 到 14 = 3.0
11 到 15 = 3.9583333
11 到 16 = 4.9583335
11 到 17 = 5.9583335
11 到 18 = 6.9583335
11 到 3581

展望未来，我找到了确定日期差异的最确凿方法

Calendar cre_calendar = new GregorianCalendar((2013), (1), 11);
        Calendar exp_calendar = new GregorianCalendar((2013), (1), 19);
        Calendar maxDays = new GregorianCalendar(((2013)), (12), 31);

        if (exp_calendar.get(Calendar.DAY_OF_YEAR) < cre_calendar
                .get(Calendar.DAY_OF_YEAR)) {
            System.out
                    .println((exp_calendar.get(Calendar.DAY_OF_YEAR) + maxDays
                            .get(Calendar.DAY_OF_YEAR))
                            - cre_calendar.get(Calendar.DAY_OF_YEAR));
        } else {
            System.out.println((exp_calendar.get(Calendar.DAY_OF_YEAR))
                    - cre_calendar.get(Calendar.DAY_OF_YEAR));
        }
于 2013-01-11T00:20:19.793 回答