java - HHMM 格式的总计时间

Question

所以我有一系列的时间:

ArrayList<String> times = new ArrayList<String>();
times.add("1240");
times.add("1028");
times.add("0923");
times.add("2023");

我不想找到这些时间之间经过的总小时数，但我不知道如何找到!

例如:

"1240 to 1028" would be 11hrs20 + 10hrs28 in travel time.

To go from 12h40 on one day to 10h28 next day, you need 11h20 (going to midnight), then 10h28. Quite clear.

Answer 1

首先我们需要一种将字符串转换为线性时间表示的方法:

// Given a string of the form HHMM, this returns the number of minutes after midnight.
// For example: timeStringToMinutes("0000") -> 0.
// timeStringToMinutes("0015") -> 15.
// timeStringToMinutes("0100") -> 60.
// timeStringToMinutes("0837") -> 517.
// timeStringToMinutes("2359") -> 1439.
static int timeStringToMinutes(String s) {
    return Integer.parseInt(s.substring(0, 2)) * 60 + Integer.parseInt(s.substring(2, 4));
}

接下来我们定义一个函数来计算时间差:

// Example: forwardNumberOfMinutes("1240", "1028") -> 1308.
static int forwardNumberOfMinutes(String start, String end) {
    int from = timeStringToMinutes(start);
    int to   = timeStringToMinutes(end);
    if (to < from)
        to += 1440;  // 1 day, or 24 hours
    return to - from;
}

最后我们定义一个函数将线性时间转换为小时和分钟:

// Example: minutesToTimeString(1308) -> "2148" (21 hr 48 min).
static minutesToTimeString(int n) {
    return String.format("%02d%02d", n / 60, n % 60);
}