如何根据时间检查日间周期或夜间周期？

Question

您好我有一个时间列表，但我想根据时间列表检查时间是天周期还是夜间周期。

1. 示例夜间循环限制00:00至12:00
2. 示例日周期限制12:00至00:00

尝试{

            SimpleDateFormat formatter = new SimpleDateFormat("HH:mm");
            Date date_from = formatter.parse("00:00");
            Date date_to = formatter.parse("12:00");
            Date dateNow = formatter.parse("07:30");
            if (date_from.before(dateNow)) {
                check = "nightCycle";
            } else if (dateNow.before(date_to)) {
                check = "nightCycle";
            } else if (dateNow.after(date_from)) {
                check = "nightCycle";
            } else {
                check = "DayCycle";
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

Answer 1

您需要根据午夜时间间隔使用不同的条件。画一个小图，这有助于使条件正确。

if (date_from.before(date_to)) { // they are on the same day
    if (dateNow.after(date_from) && dateNow.before(date_to)) {
        check = "nightCycle";
    } else {
        check = "dayCycle";
    }
 } else { // interval crossing midnight
    if (dateNow.before(date_to) || dateNow.after(date_from)) {
        check = "nightCycle";
    } else {
        check = "dayCycle";
    }
 }

Answer 2

Just in case any one wants a complete working code modified henry and Shanmugapriyan's solutions a little bit.

SimpleDateFormat formatter = new SimpleDateFormat("HH:mm");
Date date_from = formatter.parse("00:00");
Date date_to = formatter.parse("08:00");
Date dateNow = formatter.parse(formatter.format(new Date()));

System.out.println("date_to: " + date_from);
System.out.println("date_to: " + date_to);
System.out.println("dateNow: " + dateNow);

String check = "dayCycle";
if (date_from.before(date_to)) { // they are on the same day
    if (dateNow.after(date_from) && dateNow.before(date_to)) {
        check = "nightCycle";
    } else {
        check = "dayCycle";
    }
} else { // interval crossing midnight
    if (dateNow.before(date_to) || dateNow.after(date_from)) {
        check = "nightCycle";
    } else {
        check = "dayCycle";
    }
}
System.out.println("Cycle is " + check);