nanotime

问题 Java 8\'s java.time.Instant stores in \"nanosecond resolution\", but using Instant.now() only provides millisecond resolution... Instant instant = Instant.now(); System.out.println(instant); System.out.println(instant.getNano()); Result... 2013-12-19T18:22:39.639Z 639000000 How can I get an Instant whose value is \'now\', but with nanosecond resolution? 回答1: While default Java8 clock does not provide nanoseconds resolution, you can combine it with Java ability to measure time differences with

问题 As documented in the blog post Beware of System.nanoTime() in Java , on x86 systems, Java\'s System.nanoTime() returns the time value using a CPU specific counter. Now consider the following case I use to measure time of a call: long time1= System.nanoTime(); foo(); long time2 = System.nanoTime(); long timeSpent = time2-time1; Now in a multi-core system, it could be that after measuring time1, the thread is scheduled to a different processor whose counter is less than that of the previous CPU