如何转换为秒数？System.currentTimeMillis();
long start6=System.currentTimeMillis();
System.out.println(counter.countPrimes(100000000)+" for "+start6);
控制台显示我。我看不出那是多少秒。5761455 for 1307816001290
有什么帮助吗？
TimeUnit使用 Java 5 及更高版本中内置的 TimeUnit 枚举。
long timeMillis = System.currentTimeMillis();
long timeSeconds = TimeUnit.MILLISECONDS.toSeconds(timeMillis);
long start = System.currentTimeMillis();
counter.countPrimes(1000000);
long end = System.currentTimeMillis();
System.out.println("Took : " + ((end - start) / 1000));
更新
更准确的解决方案是：
final long start = System.nanoTime();
counter.countPrimes(1000000);
final long end = System.nanoTime();
System.out.println("Took: " + ((end - start) / 1000000) + "ms");
System.out.println("Took: " + (end - start)/ 1000000000 + " seconds");
