import java.util.concurrent.TimeUnit;

 import org.junit.Test;

 import com.google.common.base.Stopwatch;

 public class GuavaTest {

     @Test

     public void testStopwatch() throws InterruptedException {

         // 创建自动start的计时器

         Stopwatch watch = Stopwatch.createStarted();

         Thread.sleep(1000L);

         long time = watch.elapsed(TimeUnit.MILLISECONDS);

         // 结果1003

         System.out.println("代码执行时长：" + time);

         // 创建非自动start的计时器

         // 累计了start到stop的时间

         Stopwatch watch1 = Stopwatch.createUnstarted();

         watch1.start();

         Thread.sleep(1000L);

         watch1.stop();

         watch1.start();

         Thread.sleep(500L);

         time = watch1.elapsed(TimeUnit.MILLISECONDS);

         // 结果1500

         System.out.println("代码执行时长：" + time);

         Stopwatch watch2 = Stopwatch.createUnstarted();

         watch2.start();

         Thread.sleep(1000L);

         time = watch2.elapsed(TimeUnit.MILLISECONDS);

         // 结果1000

         System.out.println("代码执行时长：" + time);

     }

 }

代码执行时长：1003

代码执行时长：1500

代码执行时长：1000