计算运行时间

public class Main {

  public static void main(String[] args) throws Exception {

    // Get current time
    /**
    nowjava 提供 
    **/

    long start = System.currentTimeMillis();

    System.out.println(start);

    // Do something ...


    // Get elapsed time in milliseconds

    long elapsedTimeMillis = System.currentTimeMillis() - start;


    // Get elapsed time in seconds

    float elapsedTimeSec = elapsedTimeMillis / 1000F;
/** 来自 时 代      J a v a   公   众 号 - nowjava.com**/

    // Get elapsed time in minutes

    float elapsedTimeMin = elapsedTimeMillis / (60 * 1000F);


    // Get elapsed time in hours

    float elapsedTimeHour =