Java uses Google Guava for time calculation
Google Guava is a Java class library that provides several user-friendly, efficient, and carefully designed tools and collection classes to simplify some common tasks in Java programming. This includes time calculation.
Before starting to use Google Guava for time calculation, it is necessary to add the corresponding dependency library to the project. Here are the Maven coordinates of Guava:
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>30.1-jre</version>
</dependency>
By adding the Maven dependency mentioned above, the Guava class library can be introduced into the project and its time calculation function can be used.
Here is a complete example of using Guava for time calculation:
import com.google.common.base.Stopwatch;
import java.util.concurrent.TimeUnit;
public class TimeCalculationExample {
public static void main(String[] args) throws InterruptedException {
Stopwatch stopwatch = Stopwatch.createStarted();
//Simulate time-consuming tasks
Thread.sleep(2000);
stopwatch.stop();
long elapsedMillis = stopwatch.elapsed(TimeUnit.MILLISECONDS);
System. out. println ("Task execution time:"+elapsedMillis+"milliseconds");
}
}
In the above code, we first created a 'Stopwatch' instance for timing. Then use the 'start()' method of 'stopwatch' to start the timer and execute a time-consuming task (using 'Thread. sleep (2000)' here to simulate a time-consuming operation). Finally, use the 'stop()' method of 'stopwatch' to stop the timer and use the 'elapsed()' method to obtain the task execution time. By specifying the Unit of time of the 'elapsed()' method as' TimeUnit. MILLISECONDS', we obtain the millisecond representation of the task execution time.
Summary:
When using Google Guava for time calculation, we can easily perform timing operations through the 'Stopwatch' class. Create a timer instance using the 'createStarted()' method, start the timer using the 'start()' method, stop the timer using the 'stop()' method, and obtain the task execution time using the 'elapsed()' method. We can specify the return Unit of time to better show the task execution time.
