How to convert nanoseconds to seconds using the TimeUnit enum?

Question

How to convert a value from nanoseconds to seconds?

Here\'s the code segment:

import java.io.*;
import java.util.concurrent.*; 
..

class Stamper          


        

Answer 1

JDK9+ solution using java.time.Duration

Duration.ofNanos(1_000_000L).toSeconds()

https://docs.oracle.com/javase/9/docs/api/java/time/Duration.html#ofNanos-long-

https://docs.oracle.com/javase/9/docs/api/java/time/Duration.html#toSeconds--

Answer 2

This will convert a time to seconds in a double format, which is more precise than an integer value:

double elapsedTimeInSeconds = TimeUnit.MILLISECONDS.convert(elapsedTime, TimeUnit.NANOSECONDS) / 1000.0;

Answer 3

You should write :

    long startTime = System.nanoTime();        
    long estimatedTime = System.nanoTime() - startTime;

Assigning the endTime in a variable might cause a few nanoseconds. In this approach you will get the exact elapsed time.

And then:

TimeUnit.SECONDS.convert(estimatedTime, TimeUnit.NANOSECONDS)

Answer 4

In Java 8 or Kotlin, I use Duration.ofNanos(1_000_000_000) like

val duration = Duration.ofNanos(1_000_000_000)
logger.info(String.format("%d %02dm %02ds %03d",
                elapse, duration.toMinutes(), duration.toSeconds(), duration.toMillis()))

Read more https://docs.oracle.com/javase/8/docs/api/java/time/Duration.html

Answer 5

TimeUnit Enum

The following expression uses the TimeUnit enum (Java 5 and later) to convert from nanoseconds to seconds:

TimeUnit.SECONDS.convert(elapsedTime, TimeUnit.NANOSECONDS)

Answer 6

TimeUnit is an enum, so you can't create a new one.

The following will convert 1000000000000ns to seconds.

TimeUnit.NANOSECONDS.toSeconds(1000000000000L);