In Java, you can use the following ways to measure elapsed time in Java. 1. System.nanoTime() This is the recommended solution to measure elapsed time in Java. ExecutionTime1.java package com.mkyong.time; import java.util.concurrent.TimeUnit; public class ExecutionTime1 { public static void...
下面是一个使用System.currentTimeMillis()方法实现的计时器示例代码: longstartTime=System.currentTimeMillis();// 执行一些操作longendTime=System.currentTimeMillis();longelapsedTime=endTime-startTime;System.out.println("操作耗时:"+elapsedTime+"毫秒"); 1. 2. 3. 4. 5. 以上代码会输出执行某个操作所...
publicclassMain{publicstaticvoidmain(String[]args){longstartTime=System.nanoTime();// 执行一些操作...longendTime=System.nanoTime();longelapsedTime=endTime-startTime;System.out.println("程序执行时间:"+elapsedTime+"纳秒");}} 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 在上面的示例...
sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1); sun.misc.PerfCounter.getFindClasses().increment(); } }if(resolve) { resolveClass(c); }returnc; } } ClassFileTransformer.transform() 和 字节码增强 ClassFileTransformer.transform() 中可以对指定的类进行增强,我们可以选择代码生成库...
2.1.currentTimeMillis() When we encounter a requirement to measure elapsed time in Java, we may try to do it like: longstart=System.currentTimeMillis();// ...longfinish=System.currentTimeMillis();longtimeElapsed=finish - start; If we look at the code it makes perfect sense. We get a ...
.convert(getNanoTime(),TimeUnit.NANOSECONDS);}// @since 2.4 老API 这叫获取启动的时间(啥时候启动的)publiclonggetStartTime(){if(this.runningState==State.UNSTARTED){thrownewIllegalStateException("Stopwatch has not been started");}// System.nanoTime is for elapsed timereturnthis.startTimeMillis;...
c=findClass(name);sun.misc.PerfCounter.getParentDelegationTime().addTime(t1-t0);sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1);sun.misc.PerfCounter.getFindClasses().increment();}}//这一段就是加载过程中的链接Linking部分,分为验证、准备,解析三个部分。// 运行时加载类,默认是无法...
l=System.currentTimeMillis();try(varexecutor=Executors.newVirtualThreadPerTaskExecutor()){IntStream.range(0,size).forEach(i->{executor.submit(()->{Thread.sleep(Duration.ofSeconds(1));//System.out.println(i);returni;});});}System.out.printf("elapsed time: %dms\n",System.currentTime...
long t1 = System.nanoTime(); // 自己加载,从指定路径 c = findClass(name); // this is the defining class loader; record the stats sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0); sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1); ...
TimeZone represents a time zone offset, and also figures out daylight savings. Typically, you get a TimeZone using getDefault which creates a TimeZone based on the time zone where the program is running. For example, for a program running in Japan, getDefault creates a TimeZone object ...