计算Java 8中两个日期之间的天数

Question

我知道有很多关于如何获得的问题,但我想要和使用新的Java 8 Date api的例子.我也知道JodaTime库,但我想要一种没有外部库的工作方式.

功能需要抱怨这些限制:

1. 防止日期保存时间错误
2. 输入是两个Date的对象(没有时间,我知道localdatetime,但我需要处理日期实例)

Answer 1

如果您想要逻辑日历日,请使用以下DAYS.between()方法java.time.temporal.ChronoUnit:

LocalDate dateBefore;
LocalDate dateAfter;
long daysBetween = DAYS.between(dateBefore, dateAfter);

如果你想要24小时的文字,(持续时间),你可以使用Duration该类:

LocalDate today = LocalDate.now()
LocalDate yesterday = today.minusDays(1);
// Duration oneDay = Duration.between(today, yesterday); // throws an exception
Duration.between(today.atStartOfDay(), yesterday.atStartOfDay()).toDays() // another option

有关更多信息,请参阅此文档(以及其他文档:Oracle的Java 8).

Answer 2

根据VGR的评论,您可以使用以下内容:

ChronoUnit.DAYS.between(firstDate, secondDate)

Answer 3

你可以使用until():

LocalDate independenceDay = LocalDate.of(2014, Month.JULY, 4);
LocalDate christmas = LocalDate.of(2014, Month.DECEMBER, 25);

System.out.println("Until christmas: " + independenceDay.until(christmas));
System.out.println("Until christmas (with crono): " + independenceDay.until(christmas, ChronoUnit.DAYS));

Answer 4

您可以使用DAYS.between从java.time.temporal.ChronoUnit

例如

import java.time.temporal.ChronoUnit;

public long getDaysCountBetweenDates(LocalDate dateBefore, LocalDate dateAfter) {
    return DAYS.between(dateBefore, dateAfter);
}

Answer 5

如果starDate和endDate是java.util.Date的实例

我们可以在ChronoUnit 枚举中使用下面的between（）方法

public long between(Temporal temporal1Inclusive, Temporal temporal2Exclusive) {
    //..
}

ChronoUnit.DAYS计算完成24小时的天数。

import java.time.temporal.ChronoUnit;

ChronoUnit.DAYS.between(startDate.toInstant(), endDate.toInstant());

//OR 

ChronoUnit.DAYS.between(Instant.ofEpochMilli(startDate.getTime()), Instant.ofEpochMilli(endDate.getTime()));

Answer 6

在枚举java.time.temporal.ChronoUnit中使用DAYS .以下是示例代码:

输出: *开始日期:2015-03-01和结束日期之间的天数:2016-03-03是==> 368.**开始日期:2016-03-03和结束日期之间的天数: 2015-03-01是==> -368*

package com.bitiknow.date;

import java.time.LocalDate;
import java.time.temporal.ChronoUnit;

/**
 * 
 * @author pradeep
 *
 */
public class LocalDateTimeTry {
    public static void main(String[] args) {

        // Date in String format.
        String dateString = "2015-03-01";

        // Converting date to Java8 Local date
        LocalDate startDate = LocalDate.parse(dateString);
        LocalDate endtDate = LocalDate.now();
        // Range = End date - Start date
        Long range = ChronoUnit.DAYS.between(startDate, endtDate);
        System.out.println("Number of days between the start date : " + dateString + " and end date : " + endtDate
                + " is  ==> " + range);

        range = ChronoUnit.DAYS.between(endtDate, startDate);
        System.out.println("Number of days between the start date : " + endtDate + " and end date : " + dateString
                + " is  ==> " + range);

    }

}

Answer 7

从当天获取圣诞节前的天数，试试这个

System.out.println(ChronoUnit.DAYS.between(LocalDate.now(),LocalDate.of(Year.now().getValue(), Month.DECEMBER, 25)));

Answer 8

干得好：

public class DemoDate {
    public static void main(String[] args) {
        LocalDate today = LocalDate.now();
        System.out.println("Current date: " + today);

        //add 1 month to the current date
        LocalDate date2 = today.plus(1, ChronoUnit.MONTHS);
        System.out.println("Next month: " + date2);

        // Put latest date 1st and old date 2nd in 'between' method to get -ve date difference
        long daysNegative = ChronoUnit.DAYS.between(date2, today);
        System.out.println("Days : "+daysNegative);

        // Put old date 1st and new date 2nd in 'between' method to get +ve date difference
        long datePositive = ChronoUnit.DAYS.between(today, date2);
        System.out.println("Days : "+datePositive);
    }
}

Answer 9

每个人都说要使用ChronoUnit.DAYS.between,但只是委托给你自己称之为另一种方法.所以你也可以这样做firstDate.until(secondDate, ChronoUnit.DAYS).

两者的文档实际上都提到了这两种方法,并说使用哪一种更具可读性.