详解Java中Duration类的使用方法

目录

• 简介
• Duration和Period
• 创建方法
• 通过时间单位创建
• 通过LocalDateTime或LocalTime
• 通过已有的Duration
• 解析方法
• 用法说明
• 详解
• 比较方法
• 增减方法
• 转换单位
• 取值方法

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（秒0纳秒）、1毫秒（0秒纳秒）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：

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

Duration du1 = Duration.ofHours(10); Duration duration = Duration.from(du1); 

解析方法

用法说明

用法示例

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

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

plus()/minus()方法

带TemporalUnit 类型参数进行加减：

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(); //  duration.toNanos(); // 00 

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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