Java发现时间差异

我发现时间差异时有一些问题，如果我试图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，但是当我试图找到差异，如t1 =“20:00:00”（这是今天的时间）和t2 =“08:00:00”（这是第二天早上），我希望输出为12小时，但我得到输出错误。 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); } 

Answer 1

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

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()); } } 

哪个输出

 12 hours 00 minutes 

在我的代码中我似乎无法回答的问题是你为什么这样做s4 = s2+s3; ，基本上添加12:00到24:00

Answer 2

在这里查看一些选项

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 

Answer 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(); 

Answer 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"); } 

产量

 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