我想使用System.currentTimeMillis()记录用户在程序中开始某项操作时的时间。当他完成时,我将从start变量中减去当前的System.currentTimeMillis(),并且我希望使用人类可读的格式显示他们所经过的时间,例如“XX小时,XX分钟,XX秒”,甚至“XX分钟,XX秒”,因为它不太可能花费某人一个小时。

最好的方法是什么?


当前回答

这个答案与上面的一些答案相似。然而,我觉得这将是有益的,因为与其他答案不同,这将删除任何额外的逗号或空格,并处理缩写。

/**
 * Converts milliseconds to "x days, x hours, x mins, x secs"
 * 
 * @param millis
 *            The milliseconds
 * @param longFormat
 *            {@code true} to use "seconds" and "minutes" instead of "secs" and "mins"
 * @return A string representing how long in days/hours/minutes/seconds millis is.
 */
public static String millisToString(long millis, boolean longFormat) {
    if (millis < 1000) {
        return String.format("0 %s", longFormat ? "seconds" : "secs");
    }
    String[] units = {
            "day", "hour", longFormat ? "minute" : "min", longFormat ? "second" : "sec"
    };
    long[] times = new long[4];
    times[0] = TimeUnit.DAYS.convert(millis, TimeUnit.MILLISECONDS);
    millis -= TimeUnit.MILLISECONDS.convert(times[0], TimeUnit.DAYS);
    times[1] = TimeUnit.HOURS.convert(millis, TimeUnit.MILLISECONDS);
    millis -= TimeUnit.MILLISECONDS.convert(times[1], TimeUnit.HOURS);
    times[2] = TimeUnit.MINUTES.convert(millis, TimeUnit.MILLISECONDS);
    millis -= TimeUnit.MILLISECONDS.convert(times[2], TimeUnit.MINUTES);
    times[3] = TimeUnit.SECONDS.convert(millis, TimeUnit.MILLISECONDS);
    StringBuilder s = new StringBuilder();
    for (int i = 0; i < 4; i++) {
        if (times[i] > 0) {
            s.append(String.format("%d %s%s, ", times[i], units[i], times[i] == 1 ? "" : "s"));
        }
    }
    return s.toString().substring(0, s.length() - 2);
}

/**
 * Converts milliseconds to "x days, x hours, x mins, x secs"
 * 
 * @param millis
 *            The milliseconds
 * @return A string representing how long in days/hours/mins/secs millis is.
 */
public static String millisToString(long millis) {
    return millisToString(millis, false);
}

其他回答

首先,System.currentTimeMillis()和Instant.now()对于计时来说并不理想。它们都报告了挂钟时间,而计算机并不能准确地知道这个时间,而且它可能会不规律地移动,例如,如果NTP守护进程更正了系统时间,就会往回走。如果计时发生在一台机器上,那么应该使用System.nanoTime()。

其次,从Java 8开始,Java .time. duration是表示持续时间的最佳方式:

long start = System.nanoTime();
// do things...
long end = System.nanoTime();
Duration duration = Duration.ofNanos(end - start);
System.out.println(duration); // Prints "PT18M19.511627776S"
System.out.printf("%d Hours %d Minutes %d Seconds%n",
        duration.toHours(), duration.toMinutes() % 60, duration.getSeconds() % 60);
// prints "0 Hours 18 Minutes 19 Seconds"

使用java.util.concurrent.TimeUnit类:

String.format("%d min, %d sec", 
    TimeUnit.MILLISECONDS.toMinutes(millis),
    TimeUnit.MILLISECONDS.toSeconds(millis) - 
    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis))
);

注意:TimeUnit是Java 1.5规范的一部分,但是toMinutes是在Java 1.6中添加的。

为0-9的值添加前导零,只需执行以下操作:

String.format("%02d min, %02d sec", 
    TimeUnit.MILLISECONDS.toMinutes(millis),
    TimeUnit.MILLISECONDS.toSeconds(millis) - 
    TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis))
);

如果TimeUnit或toMinutes不受支持(例如在API版本9之前的Android上),使用以下公式:

int seconds = (int) (milliseconds / 1000) % 60 ;
int minutes = (int) ((milliseconds / (1000*60)) % 60);
int hours   = (int) ((milliseconds / (1000*60*60)) % 24);
//etc...

对于那些寻找Kotlin代码的人:

fun converter(millis: Long): String =
        String.format(
            "%02d : %02d : %02d",
            TimeUnit.MILLISECONDS.toHours(millis),
            TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(
                TimeUnit.MILLISECONDS.toHours(millis)
            ),
            TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(
                TimeUnit.MILLISECONDS.toMinutes(millis)
            )
        )

示例输出:09:10:26

基于@siddhadev的回答,我写了一个将毫秒转换为格式化字符串的函数:

   /**
     * Convert a millisecond duration to a string format
     * 
     * @param millis A duration to convert to a string form
     * @return A string of the form "X Days Y Hours Z Minutes A Seconds".
     */
    public static String getDurationBreakdown(long millis) {
        if(millis < 0) {
            throw new IllegalArgumentException("Duration must be greater than zero!");
        }

        long days = TimeUnit.MILLISECONDS.toDays(millis);
        millis -= TimeUnit.DAYS.toMillis(days);
        long hours = TimeUnit.MILLISECONDS.toHours(millis);
        millis -= TimeUnit.HOURS.toMillis(hours);
        long minutes = TimeUnit.MILLISECONDS.toMinutes(millis);
        millis -= TimeUnit.MINUTES.toMillis(minutes);
        long seconds = TimeUnit.MILLISECONDS.toSeconds(millis);

        StringBuilder sb = new StringBuilder(64);
        sb.append(days);
        sb.append(" Days ");
        sb.append(hours);
        sb.append(" Hours ");
        sb.append(minutes);
        sb.append(" Minutes ");
        sb.append(seconds);
        sb.append(" Seconds");

        return(sb.toString());
    }
    long startTime = System.currentTimeMillis();
    // do your work...
    long endTime=System.currentTimeMillis();
    long diff=endTime-startTime;       
    long hours=TimeUnit.MILLISECONDS.toHours(diff);
    diff=diff-(hours*60*60*1000);
    long min=TimeUnit.MILLISECONDS.toMinutes(diff);
    diff=diff-(min*60*1000);
    long seconds=TimeUnit.MILLISECONDS.toSeconds(diff);
    //hour, min and seconds variables contains the time elapsed on your work