【问题标题】：Java finding difference between timesJava发现时间之间的差异
【发布时间】：2015-10-06 03:48:45
【问题描述】：

我在查找时间之间的差异时遇到了一些问题，如果我尝试在今天的时间找到差异（比如 t1 = "08:00:00" 和 t2 = "10:00:00" 那么它给出了正确的输出，）但是当我试图找到像 t1 =“20:00:00”（今天的时间）和 t2 =“08:00:00”（第二天早上）这样的差异时，我希望输出为 12 小时但我得到了错误的输出。请帮助我。

    String t1 = "20:00:00"; 
    String t2 = "12:00:00";
    String t3 = "24:00:00";
    SimpleDateFormat sDf = new SimpleDateFormat("HH:mm:ss");
    Date d1 = sDf.parse(t1);
    Date d2 = sDf.parse(t2);
    Date d3 = sDf.parse(t3);
    long s1,s2,s3,s4,dif1,dif2,dif3,minutes,hrs;
    dif1 = d2.getTime() - d1.getTime();
    s1 = dif1/1000;
    System.out.println("s1 "+s1);
    if(s1<0){
        dif2 = d3.getTime() - d1.getTime();
        s2 = dif2/1000;
        System.out.println("s2 "+s2);
        dif3 = d2.getTime();
        s3 = dif3/1000;
        System.out.println("s3 "+s3);
        s4 = s2+s3;
        minutes = s4 / 60;
        s4 = s4 % 60;
        hrs = minutes / 60;
        minutes = minutes % 60;
        System.out.println("time difference is : "+hrs+": "+minutes+" :"+s4);
    }else{
        minutes = s1 / 60;
        s1 = s1 % 60;
        hrs = minutes / 60;
        minutes = minutes % 60;
        System.out.println("time difference is : "+hrs+": "+minutes+" :"+s1);
    }

【问题讨论】：

crunchify.com/…
认真的吗？使用 Java 8 的 Time API，使用 Joda Time，如果你真的非常绝望，使用 Calendar，但不要这样做！
这个s4 = s2+s3;对我来说似乎很奇怪，你不应该将两点之间的差加到第三点上，而不是加两次（12:00 + 24:00）吗？

标签： java time difference

【解决方案1】：

任何日期/时间操作/计算都应通过使用定义良好且经过测试的 API（如 Java 8 的 Time API 或 Joda Time）来完成

Java 8

public class TestTime {

    public static void main(String[] args) {
        // Because of the ability for the time to roll over to the next
        // day, we need the date component to make sense of it, for example
        // 24:00 is actually 00:00 of the next day ... joy
        LocalDateTime t1 = LocalTime.of(20, 00).atDate(LocalDate.now());
        LocalDateTime t2 = LocalTime.of(12, 00).atDate(LocalDate.now());
        LocalDateTime t3 = LocalTime.MIDNIGHT.atDate(LocalDate.now()).plusDays(1);

        if (t1.isAfter(t2)) {
            System.out.println("Before");
            Duration duration = Duration.between(t2, t3);
            System.out.println(format(duration));
        } else {
            System.out.println("After");
            Duration duration = Duration.between(t2, t1);
            System.out.println(format(duration));
        }
    }

    public static String format(Duration duration) {
        long hours = duration.toHours();
        duration = duration.minusHours(hours);

        return String.format("%02d hours %02d minutes", hours, duration.toMinutes());
    }

}

哪些输出

12 hours 00 minutes

我似乎无法在您的代码中回答的问题是您为什么这样做s4 = s2+s3;，基本上是将12:00 添加到24:00

【讨论】：

【解决方案2】：

查看一些选项here

如：

     LocalDate today = LocalDate.now()
     LocalDate yeasterday = today.minusDays(1);
     Duration oneDay = Duration.between(today, yesterday);
     Duration.between(today.atTime(0, 0), yesterday.atTime(0, 0)).toDays()   // another option

【讨论】：

【解决方案3】：

String time1 = "08:00:00";
String time2 = "17:00:00";

SimpleDateFormat format = new SimpleDateFormat("HH:mm:ss");
Date date1 = format.parse(time1);
Date date2 = format.parse(time2);
long difference = date2.getTime() - date1.getTime();

【讨论】：

【解决方案4】：

不使用 Java 8 或 Joda-Time，并确保不涉及本地时区 DST。

public static void printDiff(String time1, String time2) throws ParseException {
    SimpleDateFormat df = new SimpleDateFormat("HH:mm:ss");
    df.setTimeZone(TimeZone.getTimeZone("UTC"));
    int seconds = (int)(df.parse(time2).getTime() - df.parse(time1).getTime()) / 1000;
    if (seconds < 0)
        seconds += 24 * 60 * 60;
    int minutes = seconds / 60;
    int hours = minutes / 60;
    seconds %= 60;
    minutes %= 60;
    System.out.printf("There are %d hours %d minutes %d seconds from %s to %s%n",
                      hours, minutes, seconds, time1, time2);
}

测试

public static void main(String[] args) throws Exception {
    printDiff("08:00:00", "10:00:00");
    printDiff("20:00:00", "08:00:00");
    printDiff("15:47:22", "11:12:38");
    printDiff("08:00:00", "07:59:59");
    printDiff("08:00:00", "08:00:00");
}

输出

There are 2 hours 0 minutes 0 seconds from 08:00:00 to 10:00:00
There are 12 hours 0 minutes 0 seconds from 20:00:00 to 08:00:00
There are 19 hours 25 minutes 16 seconds from 15:47:22 to 11:12:38
There are 23 hours 59 minutes 59 seconds from 08:00:00 to 07:59:59
There are 0 hours 0 minutes 0 seconds from 08:00:00 to 08:00:00

【讨论】：