Java:使用 LocalDateTime 和 ChronoUnit 的时间差(以毫秒为单位)

Question

我想计算两个 LocalDateTime 对象之间的时间差(以毫秒为单位):

LocalDateTime startDate = LocalDateTime.of(2017, 11, 22, 21, 30, 30, 250);
LocalDateTime endDate = LocalDateTime.of(2017, 11, 22, 21, 30, 30, 252);
long diff = ChronoUnit.MILLIS.between(startDate, endDate)

但是，diff 的值不是我所期望的 2，而是 0。这是怎么回事？

Answer 1

我认为最后一个参数实际上是纳秒: https://docs.oracle.com/javase/8/docs/api/java/time/LocalDateTime.html#of-int-java.time.Month-int-int-int-int-int-

在我的例子中切换到 nanos 输出 2 的差异:

LocalDateTime startDate = LocalDateTime.of(2017, 11, 22, 21, 30, 30, 250);
LocalDateTime endDate = LocalDateTime.of(2017, 11, 22, 21, 30, 30, 252);
long diff = ChronoUnit.NANOS.between(startDate, endDate);

System.out.println(diff);

产量:

2

我认为由于您比较的是毫秒，因此差异正在向下舍入。