如何获得方法的执行时间? 是否有Timer实用程序类来计时任务所需的时间等?
在谷歌上的大多数搜索都返回调度线程和任务的计时器的结果,这不是我想要的。
如何获得方法的执行时间? 是否有Timer实用程序类来计时任务所需的时间等?
在谷歌上的大多数搜索都返回调度线程和任务的计时器的结果,这不是我想要的。
当前回答
为此,我们使用了AspectJ和Java注释。如果我们需要知道一个方法的执行时间,我们可以简单地注释它。更高级的版本可以使用自己的日志级别,可以在运行时启用和禁用。
public @interface Trace {
boolean showParameters();
}
@Aspect
public class TraceAspect {
[...]
@Around("tracePointcut() && @annotation(trace) && !within(TraceAspect)")
public Object traceAdvice ( ProceedingJintPoint jP, Trace trace ) {
Object result;
// initilize timer
try {
result = jp.procced();
} finally {
// calculate execution time
}
return result;
}
[...]
}
其他回答
我修改了代码,从正确答案得到的结果在几秒钟内:
long startTime = System.nanoTime();
methodCode ...
long endTime = System.nanoTime();
double duration = (double)(endTime - startTime) / (Math.pow(10, 9));
Log.v(TAG, "MethodName time (s) = " + duration);
Spring提供了一个实用工具类org.springframework.util。秒表,根据JavaDoc:
简单的秒表,允许计时多项任务,暴露 每个指定任务的总运行时间和运行时间。
用法:
StopWatch stopWatch = new StopWatch("Performance Test Result");
stopWatch.start("Method 1");
doSomething1();//method to test
stopWatch.stop();
stopWatch.start("Method 2");
doSomething2();//method to test
stopWatch.stop();
System.out.println(stopWatch.prettyPrint());
输出:
StopWatch 'Performance Test Result': running time (millis) = 12829
-----------------------------------------
ms % Task name
-----------------------------------------
11907 036% Method 1
00922 064% Method 2
方面:
@Around("execution(* my.package..*.*(..))")
public Object logTime(ProceedingJoinPoint joinPoint) throws Throwable {
StopWatch stopWatch = new StopWatch();
stopWatch.start();
Object retVal = joinPoint.proceed();
stopWatch.stop();
log.info(" execution time: " + stopWatch.getTotalTimeMillis() + " ms");
return retVal;
}
在Java 8中引入了一个名为Instant的新类。根据文件:
Instant represents the start of a nanosecond on the time line. This class is useful for generating a time stamp to represent machine time. The range of an instant requires the storage of a number larger than a long. To achieve this, the class stores a long representing epoch-seconds and an int representing nanosecond-of-second, which will always be between 0 and 999,999,999. The epoch-seconds are measured from the standard Java epoch of 1970-01-01T00:00:00Z where instants after the epoch have positive values, and earlier instants have negative values. For both the epoch-second and nanosecond parts, a larger value is always later on the time-line than a smaller value.
这可以用于:
Instant start = Instant.now();
try {
Thread.sleep(7000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Instant end = Instant.now();
System.out.println(Duration.between(start, end));
打印pt7.001。
在Spring框架中我们有一个叫做StopWatch的调用(org。Spring framework。util。StopWatch)
//measuring elapsed time using Spring StopWatch
StopWatch watch = new StopWatch();
watch.start();
for(int i=0; i< 1000; i++){
Object obj = new Object();
}
watch.stop();
System.out.println("Total execution time to create 1000 objects in Java using StopWatch in millis: "
+ watch.getTotalTimeMillis());
非常好的代码。
http://www.rgagnon.com/javadetails/java-0585.html
import java.util.concurrent.TimeUnit;
long startTime = System.currentTimeMillis();
........
........
........
long finishTime = System.currentTimeMillis();
String diff = millisToShortDHMS(finishTime - startTime);
/**
* converts time (in milliseconds) to human-readable format
* "<dd:>hh:mm:ss"
*/
public static String millisToShortDHMS(long duration) {
String res = "";
long days = TimeUnit.MILLISECONDS.toDays(duration);
long hours = TimeUnit.MILLISECONDS.toHours(duration)
- TimeUnit.DAYS.toHours(TimeUnit.MILLISECONDS.toDays(duration));
long minutes = TimeUnit.MILLISECONDS.toMinutes(duration)
- TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(duration));
long seconds = TimeUnit.MILLISECONDS.toSeconds(duration)
- TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(duration));
if (days == 0) {
res = String.format("%02d:%02d:%02d", hours, minutes, seconds);
}
else {
res = String.format("%dd%02d:%02d:%02d", days, hours, minutes, seconds);
}
return res;
}