StopWath是 apache commons lang3 包下的一個(gè)任務(wù)執(zhí)行時(shí)間監(jiān)視器，與我們平時(shí)常用的秒表的行為比較類(lèi)似，我們先看一下其中的一些重要方法：

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
<dependency>    <groupId>org.apache.commons</groupId>    <artifactId>commons-lang3</artifactId>    <version>3.6</version>
</dependency>

Apache提供的這個(gè)任務(wù)執(zhí)行監(jiān)視器功能豐富強(qiáng)大，靈活性強(qiáng)，如下經(jīng)典實(shí)用案例：

public static void main(String[] args) throws InterruptedException {    //創(chuàng)建后立即start，常用????StopWatch?watch?=?StopWatch.createStarted();// StopWatch watch = new StopWatch();    // watch.start();    Thread.sleep(1000);    System.out.println(watch.getTime());    System.out.println("統(tǒng)計(jì)從開(kāi)始到現(xiàn)在運(yùn)行時(shí)間：" + watch.getTime() + "ms");Thread.sleep(1000);    watch.split();    System.out.println("從start到此刻為止的時(shí)間：" + watch.getTime());???System.out.println("從開(kāi)始到第一個(gè)切入點(diǎn)運(yùn)行時(shí)間："?+?watch.getSplitTime());Thread.sleep(1000);    watch.split();    System.out.println("從開(kāi)始到第二個(gè)切入點(diǎn)運(yùn)行時(shí)間：" + watch.getSplitTime());    // 復(fù)位后, 重新計(jì)時(shí)    watch.reset();    watch.start();    Thread.sleep(1000);    System.out.println("重新開(kāi)始后到當(dāng)前運(yùn)行時(shí)間是：" + watch.getTime());    // 暫停 與 恢復(fù)    watch.suspend();    System.out.println("暫停2秒鐘");    Thread.sleep(2000);    // 上面suspend，這里要想重新統(tǒng)計(jì)，需要恢復(fù)一下   watch.resume();    System.out.println("恢復(fù)后執(zhí)行的時(shí)間是：" + watch.getTime());Thread.sleep(1000);????watch.stop();System.out.println("花費(fèi)的時(shí)間》》" + watch.getTime() + "ms");    // 直接轉(zhuǎn)成s    System.out.println("花費(fèi)的時(shí)間》》" + watch.getTime(TimeUnit.SECONDS) + "s");
}