问题描述
My heart is bleeding internally after having to go so deep to subtract two dates to calculate the span in number of days:我的心脏在内脏出血后必须如此深入，以减去两个日期，以计算天数： > GregorianCalendar c1 = new GregorianCalendar（）;
GregorianCalendar c2 = new GregorianCalendar（）;
c1.set（2000，1，1）;
c2.set（2010,1，1）;
long span = c2.getTimeInMillis（） - c1.getTimeInMillis（）;
GregorianCalendar c3 = new GregorianCalendar（）;
c3.setTimeInMillis（span）;
long numberOfMSInADay = 1000 * 60 * 60 * 24;
System.out.println（c3.getTimeInMillis（）/ numberOfMSInADay）; // 3653
GregorianCalendar c1 = new GregorianCalendar(); GregorianCalendar c2 = new GregorianCalendar(); c1.set(2000, 1, 1); c2.set(2010,1, 1); long span = c2.getTimeInMillis() - c1.getTimeInMillis(); GregorianCalendar c3 = new GregorianCalendar(); c3.setTimeInMillis(span); long numberOfMSInADay = 1000*60*60*24; System.out.println(c3.getTimeInMillis() / numberOfMSInADay); //3653
在.NET中只有2行代码，或者您命名的任何现代语言。
where it's only 2 lines of code in .NET, or any modern language you name.
这是这个残酷的java吗？还是有一个隐藏的方法我应该知道？
Is this atrocious of java? Or is there a hidden method I should know?
而不是使用GregorianCalendar，可以在util中使用Date类吗？如果是这样，我应该注意1970年的微妙事情吗？
Instead of using GregorianCalendar, is it okay to use Date class in util? If so, should I watch out for subtle things like the year 1970?
谢谢
推荐答案
这是标准Java API中最大的史诗故障之一。有一点耐心，那么你会得到你的解决方案的新的日期和时间API API （最有可能）将被包含在即将到来的Java 8中。
It's indeed one of the biggest epic failures in the standard Java API. Have a bit of patience, then you'll get your solution in flavor of the new Date and Time API specified by JSR 310 / ThreeTen which is (most likely) going to be included in the upcoming Java 8.
在此之前，您可以通过。
Until then, you can get away with JodaTime.
DateTime dt1 = new DateTime(2000, 1, 1, 0, 0, 0, 0);
DateTime dt2 = new DateTime(2010, 1, 1, 0, 0, 0, 0);
int days = Days.daysBetween(dt1, dt2).getDays();
它的创建者Stephen Colebourne是JSR 310背后的家伙，所以看起来非常相似。
Its creator, Stephen Colebourne, is by the way the guy behind JSR 310, so it'll look much similar.
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