有没有Java的秒表？

有没有Java的秒表？ 因为在谷歌我只能find秒表的代码，他们不工作，他们给我总是0毫秒。

我发现这个代码不起作用，但我不明白为什么，因为代码对我来说看起来很好。

public class StopWatch { private long startTime = 0; private long stopTime = 0; private boolean running = false; public void start() { this.startTime = System.currentTimeMillis(); this.running = true; } public void stop() { this.stopTime = System.currentTimeMillis(); this.running = false; } //elaspsed time in milliseconds public long getElapsedTime() { long elapsed; if (running) { elapsed = (System.currentTimeMillis() - startTime); } else { elapsed = (stopTime - startTime); } return elapsed; } //elaspsed time in seconds public long getElapsedTimeSecs() { long elapsed; if (running) { elapsed = ((System.currentTimeMillis() - startTime) / 1000); } else { elapsed = ((stopTime - startTime) / 1000); } return elapsed; } } 

Answer 1

你会find一个

http://commons.apache.org/lang/

这叫

 org.apache.commons.lang.time.StopWatch 

但它大体上和你的一样。 如果你在更精确的使用

 System.nanoTime() 

这里也看到这个问题：

用Java测量开销

Answer 2

使用番石榴的秒表类 。

一个以纳秒为单位度量经过时间的对象。 使用这个类来测量已用时间非常有用，而不是直接调用System.nanoTime（），原因如下：

• 出于testing或性能原因，可以替代备用时间源。
• 如nanoTime所logging的，返回的值没有绝对的含义，只能解释为相对于nanoTime在不同时间返回的另一个时间戳。 秒表是一个更有效的抽象，因为它只暴露这些相对值，而不是绝对值。

 Stopwatch stopwatch = Stopwatch.createStarted(); doSomething(); stopwatch.stop(); // optional long millis = stopwatch.elapsedMillis(); log.info("that took: " + stopwatch); // formatted string like "12.3 ms" 

Answer 3

Spring提供了一个优雅的StopWatch类。

 StopWatch stopWatch = new StopWatch(); stopWatch.start(); // Do something stopWatch.stop(); System.out.println(stopWatch.getTotalTimeMillis()); 

Answer 4

现在你可以尝试像这样：

 Instant starts = Instant.now(); Thread.sleep(10); Instant ends = Instant.now(); System.out.println(Duration.between(starts, ends)); 

输出在ISO 8601中。

Answer 5

代码不起作用，因为getElapsedTimeSecs（）中的已variablesvariables不是float / double。

Answer 6

使用System.currentTimeMillis()获取开始时间和结束时间并计算差异。

 class TimeTest1 { public static void main(String[] args) { long startTime = System.currentTimeMillis(); long total = 0; for (int i = 0; i < 10000000; i++) { total += i; } long stopTime = System.currentTimeMillis(); long elapsedTime = stopTime - startTime; System.out.println(elapsedTime); } } 

更多信息在这个教程

Answer 7

有没有内置的秒表工具，但从JSR-310（Java 8时间），你可以做到这一点。

 ZonedDateTime now = ZonedDateTime.now(); // Do stuff long seconds = now.until(ZonedDateTime.now(), ChronoUnit.SECONDS); 

我没有正确的基准，但我猜想使用番石榴的秒表更有效。

Answer 8

尝试这个

 import java.awt.event.*; import java.awt.*; import javax.swing.*; public class millis extends JFrame implements ActionListener, Runnable { private long startTime; private final static java.text.SimpleDateFormat timerFormat = new java.text.SimpleDateFormat("mm : ss.SSS"); private final JButton startStopButton= new JButton("Start/stop"); private Thread updater; private boolean isRunning= false; private final Runnable displayUpdater= new Runnable() { public void run() { displayElapsedTime(System.currentTimeMillis() - millis.this.startTime); } }; public void actionPerformed(ActionEvent ae) { if(isRunning) { long elapsed= System.currentTimeMillis() - startTime; isRunning= false; try { updater.join(); // Wait for updater to finish } catch(InterruptedException ie) {} displayElapsedTime(elapsed); // Display the end-result } else { startTime= System.currentTimeMillis(); isRunning= true; updater= new Thread(this); updater.start(); } } private void displayElapsedTime(long elapsedTime) { startStopButton.setText(timerFormat.format(new java.util.Date(elapsedTime))); } public void run() { try { while(isRunning) { SwingUtilities.invokeAndWait(displayUpdater); Thread.sleep(50); } } catch(java.lang.reflect.InvocationTargetException ite) { ite.printStackTrace(System.err); // Should never happen! } catch(InterruptedException ie) {} // Ignore and return! } public millis() { startStopButton.addActionListener(this); getContentPane().add(startStopButton); setSize(100,50); setVisible(true); } public static void main(String[] arg) { new Stopwatch().addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } }); millis s=new millis(); s.run(); } } 

Answer 9

试试这个http://introcs.cs.princeton.edu/java/stdlib/Stopwatch.java.html

这很容易

 Stopwatch st = new Stopwatch(); // Do smth. here double time = st.elapsedTime(); // the result in millis 

这个类是stdlib.jar的一部分

Answer 10

简单的开箱秒表课程：

 import java.time.Duration; import java.time.Instant; public class StopWatch { Instant startTime, endTime; Duration duration; boolean isRunning = false; public void start() { if (isRunning) { throw new RuntimeException("Stopwatch is already running."); } this.isRunning = true; startTime = Instant.now(); } public Duration stop() { this.endTime = Instant.now(); if (!isRunning) { throw new RuntimeException("Stopwatch has not been started yet"); } isRunning = false; Duration result = Duration.between(startTime, endTime); if (this.duration == null) { this.duration = result; } else { this.duration = duration.plus(result); } return this.getElapsedTime(); } public Duration getElapsedTime() { return this.duration; } public void reset() { if (this.isRunning) { this.stop(); } this.duration = null; } } 

用法：

 StopWatch sw = new StopWatch(); sw.start(); // doWork() sw.stop(); System.out.println( sw.getElapsedTime().toMillis() + "ms"); 

Answer 11

尝试这个：

 /* * calculates elapsed time in the form hrs:mins:secs */ public class StopWatch { private Date startTime; public void startTiming() { startTime = new Date(); } public String stopTiming() { Date stopTime = new Date(); long timediff = (stopTime.getTime() - startTime.getTime())/1000L; return(DateUtils.formatElapsedTime(timediff)); } } 

使用：

 StopWatch sw = new StopWatch(); ... sw.startTiming(); ... String interval = sw.stopTiming(); 

Answer 12

user1007522，我不知道为什么你的代码不起作用（看起来像已经评论过），但我刚刚从com.google.common.base.Stopwatch获得0毫秒相同的问题。

我在做

 Stopwatch stopwatch = new Stopwatch(); doSomething(); logger.info("test took:" + stopwatch); 

现在我在做

 Stopwatch stopwatch = new Stopwatch().start(); doSomething(); stopwatch.stop(); logger.info("test took:" + stopwatch); 

它工作，我得到“testing了：26.81秒”

Answer 13

你可以在这里find一个方便的：

https://github.com/varra4u/utils4j/blob/master/src/main/java/com/varra/util/StopWatch.java

用法：

 final StopWatch timer = new StopWatch(); System.out.println("Timer: " + timer); System.out.println("ElapsedTime: " + timer.getElapsedTime()); 

Answer 14

尝试这个。

 public class StopWatch { private long startTime = 0; private long stopTime = 0; public StopWatch() { startTime = System.currentTimeMillis(); } public void start() { startTime = System.currentTimeMillis(); } public void stop() { stopTime = System.currentTimeMillis(); System.out.println("StopWatch: " + getElapsedTime() + " milliseconds."); System.out.println("StopWatch: " + getElapsedTimeSecs() + " seconds."); } /** * @param process_name */ public void stop(String process_name) { stopTime = System.currentTimeMillis(); System.out.println(process_name + " StopWatch: " + getElapsedTime() + " milliseconds."); System.out.println(process_name + " StopWatch: " + getElapsedTimeSecs() + " seconds."); } //elaspsed time in milliseconds public long getElapsedTime() { return stopTime - startTime; } //elaspsed time in seconds public double getElapsedTimeSecs() { double elapsed; elapsed = ((double)(stopTime - startTime)) / 1000; return elapsed; } } 

用法：

 StopWatch watch = new StopWatch(); // do something watch.stop(); 

安慰：

 StopWatch: 143 milliseconds. StopWatch: 0.143 seconds. 

Answer 15

使用：com.google.common.base.Stopwatch，其简单易用。

 <dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>23.0</version> </dependency> 

例：

 Stopwatch stopwatch = new Stopwatch(); stopwatch.start(); "Do something" logger.debug("this task took " + stopwatch.stop().elapsedTime(TimeUnit.MILLISECONDS) + " mills"); 

这个任务花了112个工厂