org.springframework.util.StopWatch类

背景：日常开发中，要打印出逻辑代码块的消耗时长，通常呢会在逻辑代码块前后打印出当前系统时间，并减法，来计算出消耗时长。在查看SpringBoot的源码的时候，发现Spring提供了有一个叫StopWatch的类。使用起来很方便。

package com.example.studySpringBoot;

import org.junit.Test;
import org.springframework.util.StopWatch;


public class TestSpringStopWatch {

    @Test
    public void goodMorning() throws InterruptedException {
        StopWatch stopWatch = new StopWatch("早上洗漱");
        stopWatch.start("起床");
        Thread.sleep(5000);
        stopWatch.stop();
        stopWatch.start("刷牙");
        Thread.sleep(1000);
        stopWatch.stop();
        stopWatch.start("洗脸");
        Thread.sleep(3000);
        stopWatch.stop();
        System.out.println(stopWatch.prettyPrint());
    }
}

打印出来的效果看起来也很舒服：

StopWatch '早上洗漱': running time (millis) = 9001
-----------------------------------------
ms     %     Task name
-----------------------------------------
05000  056%  起床
01000  011%  刷牙
03001  033%  洗脸