时间差 - 从午夜之前到午夜之后没有约会

Posted 2021-05-05

我正在努力计算午夜后的时间：

String time = "15:00-18:05"; //Calculating OK
    //String time = "22:00-01:05"; //Not calculating properly
    String[] parts = time.split("-");

    SimpleDateFormat format = new SimpleDateFormat("HH:mm");
    Date date1 = null;
    Date date2 = null;
    Date dateMid = null;


    String dateInString = "24:00";
    try {
        dateMid = format.parse(dateInString);
    } catch (ParseException e1) {
        e1.printStackTrace();
    }

    try {
        date1 = format.parse(parts[0]);
        date2 = format.parse(parts[1]);
    } catch (ParseException e) {
        e.printStackTrace();
    }

    long difference = date2.getTime() - date1.getTime();


    if (date2.getTime()<date1.getTime()) //in case beyond midnight calculation
    {
        difference = dateMid.getTime()-difference;
    }



    int minutes = (int) ((difference / (1000*60)) % 60);
    int hours   = (int) ((difference / (1000*60*60)) % 24);

    String tot = String.format("%02d:%02d", hours,minutes);
    System.out.println("dif2: "+tot);

答案

如果你不关心夏令时的变化并且你认为世界是理想的（它不是），你可以从24小时中减去结束和开始之间的持续时间（将end视为开始和start作为结束） ：

String time = "22:00-01:05";
String[] parts = time.split("-");

LocalTime start = LocalTime.parse(parts[0]);
LocalTime end = LocalTime.parse(parts[1]);
if (start.isBefore(end)) { // normal case
    System.out.println(Duration.between(start, end));
} else { // 24 - duration between end and start, note how end and start switched places
    System.out.println(Duration.ofHours(24).minus(Duration.between(end, start)));
}