在 Java 中检查其他两个日期之间的日期时得到不正确的结果

Question

我正在使用下面的代码来检查一个小时是否介于另外两个特定时间之间：

String openHour = "08:00 AM";
String currentHour = "10:00 PM";
String closeHour = "11:00 PM"; //Change to 02:00 AM doesn't work!!!

SimpleDateFormat format = new SimpleDateFormat("hh:mm a");
Date openHourDate = format.parse(openHour);
Date currentHourDate = format.parse(currentHour);
Date closeHourDate = format.parse(closeHour);

Calendar openCalendar = Calendar.getInstance();
openCalendar.setTime(openHourDate);

Calendar currentCalendar = Calendar.getInstance();
currentCalendar.setTime(currentHourDate);

Calendar closeCalendar = Calendar.getInstance();
closeCalendar.setTime(closeHourDate);

Date open = openCalendar.getTime();
Date current = currentCalendar.getTime();
Date close = closeCalendar.getTime();

if (current.after(open) && current.before(close)) {
    System.out.println("Correct!");
} else {
    System.out.println("Incorrect!");
}

如果currentHour 是"10:00 PM"，正如您在我的代码中看到的那样，一切正常，但如果我将其更改为"02:00 AM"，即使currentHour 介于两者之间，代码也不会按预期工作08:00 AM 和 02:00 AM。如何解决？

Answer 1

这是一个使用LocalTime 的解决方案，它还可以正确处理午夜之后的当前和关闭时间。

String openHour = "08:00 AM";
String currentHour = "01:00 PM";
String closeHour = "02:00 AM";

DateTimeFormatter formatter = DateTimeFormatter.ofPattern( "hh:mm a" , Locale.US );
LocalTime openTime = LocalTime.parse(openHour, formatter);
LocalTime currentTime  = LocalTime.parse(currentHour, formatter);
LocalTime closeTime = LocalTime.parse(closeHour, formatter);

boolean isOpen = false;
if (closeTime.isAfter(openTime)) {
  if (openTime.isBefore(currentTime) && closeTime.isAfter(currentTime)) {
    isOpen = true;
  }
} else if (currentTime.isAfter(openTime) || currentTime.isBefore(closeTime)) {
  isOpen = true;
}

if (isOpen) {
  System.out.println("We are open");
} else {
  System.out.println("We are closed");
}

Answer 2

正如迈克尔·普拉特建议的那样，只需要滚动一天：

import java.util.*;
import java.text.*;

public class Foo {
  public static void main(String[] args) throws Exception {

    String openHour = "08:00 AM";
    String currentHour = "10:00 PM";
    String closeHour = "11:00 PM"; //Change to 02:00 AM doesn't work!!!

    SimpleDateFormat format = new SimpleDateFormat("hh:mm a");
    Date openHourDate = format.parse(openHour);
    Date currentHourDate = format.parse(currentHour);
    Date closeHourDate = format.parse(closeHour);

    Calendar openCalendar = Calendar.getInstance();
    openCalendar.setTime(openHourDate);

    Calendar currentCalendar = Calendar.getInstance();
    currentCalendar.setTime(currentHourDate);

    Calendar closeCalendar = Calendar.getInstance();
    closeCalendar.setTime(closeHourDate);

    if (closeCalendar.before(openCalendar)) {
      closeCalendar.add(Calendar.DAY_OF_YEAR, 1);
    }

    Date open = openCalendar.getTime();
    Date current = currentCalendar.getTime();
    Date close = closeCalendar.getTime();

    if (current.after(open) && current.before(close)) {
      System.out.println("Correct!");
    } else {
      System.out.println("Incorrect!");
    }
  }
}