详解Java中Duration类的使用方法

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（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：

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();   // 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();     //

来源：https://blog.csdn.net/feiying0canglang/article/details/124918218