详解Java中Duration类的使用方法

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小小草 2023年3月25日 21:04 发表

摘要：Duration类通过秒和纳秒相结合来描述一个时间量，最高精度是纳秒。本文将通过示例详细为大家讲讲Duration类的使用，需要的可以参考一下

简介

本文用示例介绍java的Duration的用法。

Duration和Period

说明

Duration类通过秒和纳秒相结合来描述一个时间量，最高精度是纳秒。时间量可以为正也可以为负，比如1天（86400秒0纳秒）、-1天（-86400秒0纳秒）、1年（31556952秒0纳秒）、1毫秒（0秒1000000纳秒）等。

Period类通过年、月、日相结合来描述一个时间量，最高精度是天。时间量可以为正也可以为负，例如2年（2年0个月0天）、3个月（0年3个月0天）、4天（0年0月4天）等。

这两个类是不可变的、线程安全的、最终类。都是JDK8新增的。

Period用法

见：详解Java中Period类的使用方法

创建方法

通过时间单位创建

基于天、时、分、秒、纳秒创建。

ofDays(), ofHours(), ofMillis(), ofMinutes(), ofNanos(), ofSeconds()。例如：

1	`Duration fromDays = Duration.ofDays(1);`

通过LocalDateTime或LocalTime

通过LocalDateTime或者LocalTime 类，然后使用between获取创建Duration。

LocalDateTime start = LocalDateTime.of(2022, 1, 1, 8, 0, 0);

LocalDateTime end = LocalDateTime.of(2022, 1, 2, 8, 30, 30);

Duration duration = Duration.between(start, end);

通过已有的Duration

1 2	`Duration du1 = Duration.ofHours(10);` `Duration duration = Duration.from(du1);`

解析方法

用法说明

用法示例

1 2	`Duration fromChar1 = Duration.parse("P1DT1H10M10.5S");` `Duration fromChar2 = Duration.parse("PT10M");`

格式说明

采用ISO-8601时间格式。格式为：PnYnMnDTnHnMnS （n为个数）

例如：P1Y2M10DT2H30M15.03S

P：开始标记

1Y：一年

2M：两个月

10D：十天

T：日期和时间的分割标记

2H：两个小时

30M：三十分钟

15S：15.02秒

详解

1."P", "D", "H", "M" 和 "S"可以是大写或者小写（建议大写）

2.可以用“-”表示负数

示例大全

"PT20.345S" -- parses as "20.345 seconds"
"PT15M" -- parses as "15 minutes" (where a minute is 60 seconds)
"PT10H" -- parses as "10 hours" (where an hour is 3600 seconds)
"P2D" -- parses as "2 days" (where a day is 24 hours or 86400 seconds)
"P2DT3H4M" -- parses as "2 days, 3 hours and 4 minutes"
"P-6H3M" -- parses as "-6 hours and +3 minutes"
"-P6H3M" -- parses as "-6 hours and -3 minutes"
"-P-6H+3M" -- parses as "+6 hours and -3 minutes"

源码：

public final class Duration

implements TemporalAmount, Comparable<Duration>, Serializable {

//其他代码

//-----------------------------------------------------------------------

/**

* Obtains a {@code Duration} from a text string such as {@code PnDTnHnMn.nS}.

* <p>

* This will parse a textual representation of a duration, including the

* string produced by {@code toString()}. The formats accepted are based

* on the ISO-8601 duration format {@code PnDTnHnMn.nS} with days

* considered to be exactly 24 hours.

* <p>

* The string starts with an optional sign, denoted by the ASCII negative

* or positive symbol. If negative, the whole period is negated.

* The ASCII letter "P" is next in upper or lower case.

* There are then four sections, each consisting of a number and a suffix.

* The sections have suffixes in ASCII of "D", "H", "M" and "S" for

* days, hours, minutes and seconds, accepted in upper or lower case.

* The suffixes must occur in order. The ASCII letter "T" must occur before

* the first occurrence, if any, of an hour, minute or second section.

* At least one of the four sections must be present, and if "T" is present

* there must be at least one section after the "T".

* The number part of each section must consist of one or more ASCII digits.

* The number may be prefixed by the ASCII negative or positive symbol.

* The number of days, hours and minutes must parse to an {@code long}.

* The number of seconds must parse to an {@code long} with optional fraction.

* The decimal point may be either a dot or a comma.

* The fractional part may have from zero to 9 digits.

* <p>

* The leading plus/minus sign, and negative values for other units are

* not part of the ISO-8601 standard.

* <p>

* Examples:

* <pre>

* "PT20.345S" -- parses as "20.345 seconds"

* "PT15M" -- parses as "15 minutes" (where a minute is 60 seconds)

* "PT10H" -- parses as "10 hours" (where an hour is 3600 seconds)

* "P2D" -- parses as "2 days" (where a day is 24 hours or 86400 seconds)

* "P2DT3H4M" -- parses as "2 days, 3 hours and 4 minutes"

* "P-6H3M" -- parses as "-6 hours and +3 minutes"

* "-P6H3M" -- parses as "-6 hours and -3 minutes"

* "-P-6H+3M" -- parses as "+6 hours and -3 minutes"

* </pre>

*

* @param text the text to parse, not null

* @return the parsed duration, not null

* @throws DateTimeParseException if the text cannot be parsed to a duration

*/

public static Duration parse(CharSequence text) {

......

}

比较方法

比较两个时间的差

Instant start = Instant.parse("2017-10-03T10:15:30.00Z");

Instant end = Instant.parse("2017-10-03T10:16:30.00Z");

// start - end

Duration duration = Duration.between(start, end);

// 任何一个时间单元为负数，则返回true。true：end早于start

duration.isNegative();

Duration.between(start, end).getSeconds();

Duration.between(start, end).getNano();

增减方法

plusX()、minusX()

X表示days, hours, millis, minutes, nanos 或 seconds

1 2	`Duration duration = Duration.ofHours(2);` `Duration newDuration = duration.plusSeconds(33);`

plus()/minus()方法

带TemporalUnit 类型参数进行加减：

1 2	`Duration duration = Duration.ofHours(2);` `Duration newDuration = duration.plus(33, ChronoUnit.SECONDS);`

转换单位

可以用toX来转换为其他单位，支持：toDays, toHours, toMinutes, toMillis, toNanos

Duration duration = Duration.ofHours(2);

duration.toDays(); // 0

duration.toHours(); // 2

duration.toMinutes(); // 120

duration.toMillis(); // 7200000

duration.toNanos(); // 7200000000000

取值方法

可以用getX来获得指定位置的值，因为Duration是由秒和纳秒组成，所以只能获得秒和纳秒：

Duration duration = Duration.ofHours(2);

duration.getSeconds(); //7200

duration.getNano(); //

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