如何计算日期差？

Question

我正在使用java.util.Date类，并且想要比较date对象和当前时间。

输出格式必须是这样：

"... years , ... months , ... days , ...hours , ... minutes , ... seconds.

这是我的代码：

public static void main(String[] args) {
        Calendar calendar = new GregorianCalendar(2022, 1 , 25 , 12 , 20 , 33);
        Date now = new Date(); //Tue Feb 25 11:49:05 IRST 2020
        Date date = calendar.getTime(); //Fri Feb 25 12:20:33 IRST 2022
}

有一种简单的方法可以计算出来吗？

Answer 1

Java 8 Date/Time API在比较日期方面很灵活。

示例：

LocalDate currentDate = LocalDate.now();
LocalDate previousDate = LocalDate.of(2000, 7, 1);

assertThat(currentDate.isAfter(previousDate), is(true));

更多示例here。

Answer 2

使用Java Instant

Instant start, end;
Duration duration = Duration.between(start, stop);
long hours = dur.toHours();
long minutes = dur.toMinutes();

Answer 3

由于年，月和日的不同，有一个java.time.Period您可以轻松地使用它来获取所需的内容：

public static void main(String[] args) {
    LocalDateTime localDateTime = LocalDateTime.of(2022, 1 , 25 , 12 , 20 , 33);
    LocalDateTime now = LocalDateTime.now();

    // get the difference in years, months and days
    Period p = Period.between(now.toLocalDate(), localDateTime.toLocalDate());

    // and print the result(s)
    System.out.println("Difference between " + localDateTime.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
            + " and " + now.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME) + " is:\n"
            + p.getYears() + " years, " + p.getMonths() + " months, " + p.getDays() + " days");
}

此代码示例的输出将是（当然，取决于当天）：
Difference between 2022-01-25T12:20:33 and 2020-02-25T10:52:43.327 is:
1 years, 11 months, 0 days