1.
Java, 특정 로직에 대한 성능 확인(속도 체크)<br />김용환<br />

2.
System.currentTimeMillis()<br />소스<br />long startTime = System.currentTimeMillis();Thread.sleep(1000);long estimatedTime = System.currentTimeMillis() - startTime;System.out.println("took " + estimatedTime + " ms");<br />결과<br />took 1000 ms<br />

3.
System.nanoTime() <br />소스<br />long time1 = System.nanoTime();Thread.sleep(1000);long time2 = System.nanoTime();long timeSpent = time2 - time1;System.out.println("took " + timeSpent + " ns");<br />결과<br />took 1000232514 ns<br />

4.
Commons-lang의 StopWatch (2.3)<br />import org.apache.commons.lang.time.StopWatch;..StopWatchstopWatch = new StopWatch();stopWatch.reset();stopWatch.start();Thread.sleep(2000);stopWatch.stop();System.out.println(stopWatch.toString()); stopWatch.reset();stopWatch.start();Thread.sleep(5000);stopWatch.stop();System.out.println(stopWatch.toString()); stopWatch.reset();stopWatch.start();Thread.sleep(3000);stopWatch.stop();System.out.println(stopWatch.toString());<br />소스<br />0:00:02.0000:00:05.0000:00:03.000<br />결과<br />

5.
Spring core lib에 있는 util성 StopWatch (3.0)<br />소스<br />import org.springframework.util.StopWatch;...StopWatchstopWatch = new StopWatch("Stop Watch");stopWatch.start("initializing");Thread.sleep(2000);stopWatch.stop();System.out.println("took " + stopWatch.getLastTaskTimeMillis() + " ms");<br />stopWatch.start("processing");Thread.sleep(5000);stopWatch.stop();System.out.println("took " + stopWatch.getLastTaskTimeMillis() + " ms"); stopWatch.start("finalizing");Thread.sleep(3000);stopWatch.stop();System.out.println("took " + stopWatch.getLastTaskTimeMillis() + " ms"); System.out.println(stopWatch.toString());System.out.println();System.out.println(stopWatch.prettyPrint());<br />

6.
Spring core lib에 있는 util성 StopWatch (3.0)<br />결과<br />took 2000 mstook 5000 mstook 3001 msStopWatch 'Stop Watch': running time (millis) = 10001; [initializing] took 2000 = 20%; [processing] took 5000 = 50%; [finalizing] took 3001 = 30%<br />StopWatch 'Stop Watch': running time (millis) = 10001-----------------------------------------ms % Task name-----------------------------------------02000 020% initializing05000 050% processing03001 030% finalizing<br />

7.
남의 것 사용<br />그냥 인터넷에서 남들이 만든 StopWatch를 찾아서 copy&paste한다.http://www.devdaily.com/blog/post/java/stopwatch-class-that-can-be-used-for-timings-benchmarks<br />

8.
Commons-lang의 StopWatch와 Spring Util의 StopWatch비교<br />