java - java中的时间和小时

Question

import java.util.Scanner;

public class Nc3 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.println("Enter time of arrival: ");
        double time = input.nextDouble();
        int arrivalTime;
        arrivalTime = 0;
        arrivalTime += time;

        if (time % 20 != 0) {
            time %= 20;
            time = 20 - time;
            System.out.println(arrivalTime +time);
        }

        else if (((arrivalTime + time) % 100) == 60.0) {
            time += 40;
            System.out.println(arrivalTime + time);
        }
        else
            System.out.println("Now - " +arrivalTime);

    }
}

我被要求编写一个程序来获取当前时间的输入并返回下一辆公共(public)汽车离开的时间知道公共(public)汽车每 20 分钟在 00、20、40 离开，问题是如果我输入 2243 表示 22:43 我将得到 2260 而不是 2300

Answer 1

java.time

我建议您使用 java.time.Duration这是仿照ISO-8601 standards并作为 JSR-310 implementation 的一部分与 Java-8 一起引入.

演示:

import java.time.Duration;
import java.time.LocalTime;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.print("Enter time of arrival: ");
        showNextDepartureTime(input.nextLine());
    }

    static void showNextDepartureTime(String arrivalTime) {
        Duration nextDeparture = Duration.between(LocalTime.MIN, LocalTime.parse(arrivalTime));
        int remainder = nextDeparture.toMinutesPart() % 20;
        if (remainder != 0)
            nextDeparture = nextDeparture.minusMinutes(remainder).plusMinutes(20);

        System.out.printf("The next departure is at %2d:%02d", nextDeparture.toHoursPart(),
                nextDeparture.toMinutesPart());
    }
}

示例运行:

Enter time of arrival: 22:43
The next departure is at 23:00

另一个样本运行:

Enter time of arrival: 22:00
The next departure is at 22:00

更新

正如 Lino 在他的 comment 中所建议的那样，您可以按如下方式替换 if 主体:

if (remainder != 0)
    nextDeparture = nextDeparture.plusMinutes(20 - remainder);