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2,正如我所料,但是0.正在发生什么？

Answer 1

我认为那里的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 -诠释-INT-内部-

在我的情况下切换到nanos输出2的diff:

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

我认为既然你在比较millis,那么差异正在向下舍入.

Answer 2

第七个参数LocalDateTime.of是纳秒,而不是毫秒.您的时间相差.000002毫秒,或零到最近long.