Java time and date operations

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Java time and date operations

LocalDate LocalTime LocalDateTime

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;

LocalDate LocalTime LocalDateTimeFollows the international standard ISO 8601

Get current date

LocalDate ld = LocalDate.now();
int year = ld.getYear();
int month = ld.getMonth().getValue();
int day = ld.getDayOfMonth();

The month and day do not start from 0. January is 1, not 0 anymore.

BuildLocalDate

LocalDate ld = LocalDate.parse("2020-12-09");
LocalDate ld_2 = LocalDate.parse("12-09-2020", DateTimeFormatter.ofPattern("MM-dd-yyyy"));
LocalDate ld_3 = LocalDate.of(2020, 12 , 9);

LocalDate uses the ISO 8601 standard by default, and you can also specify the date format.

time

Get local time

LocalTime lt = LocalTime.now();

Hours, minutes, seconds and nanoseconds can be obtained separately

int hour = lt.getHour();
int second = lt.getSecond();
int minute = lt.getMinute();
int nano = lt.getNano();

Build to specify local time

LocalTime lt = LocalTime.parse("13:24:30");
LocalTime lt_1 = LocalTime.of(13, 24, 30, 0);
LocalTime lt_2 = LocalTime.parse("13:24:30", DateTimeFormatter.ofPattern("H:i:s"));

date time

Get the specified local time

LocalDateTime ldt = LocalDateTime.now();

You can get the year, month, day, hour, minute, second and nanosecond respectively.

int year = ldt.getYear();
int month = ldt.getMonth().getValue();
int day = ldt.getDayOfMonth();
int hour = ldt.getHour();
int second = ldt.getSecond();
int minute = ldt.getMinute();
int nano = ldt.getNano();

Build local datetime

LocalDateTime m_ldt_1 = LocalDateTime.of(2021, 6, 11, 23, 12, 24, 3000);

// 使用 LocalDate 和 LocalTime 构建
LocalDate mld = LocalDate.of(2021, 6, 11);
LocalTime mlt = LocalTime.of(23, 12, 24);
LocalDateTime m_ldt_2 = LocalDateTime.of(mld, mlt);

// 解析默认格式
LocalDateTime s_ldt_1 = LocalDateTime.parse("2021-12-13T23:12:24");
// 解析自定义格式
LocalDateTime s_ldt_2 = LocalDateTime.parse("2021-12-13 23:12:24", DateTimeFormatter.ofPattern("y-M-d H:m:s"));

Time zone

ZoneId

Get current time zone

ZoneId zoneId = ZoneId.systemDefault();

System.out.println(zoneId);

Get the specified time zone

ZoneId zoneId = ZoneId.of("America/New_York");

System.out.println(zoneId);

ZonedDateTime

Get the epoch time in the current time zone

ZonedDateTime zonedDateTime = ZonedDateTime.now();
System.out.println("本地时区" + zonedDateTime);
// 本地时区 2021-11-26T08:34:05.919145+08:00[Asia/Shanghai]

Get this same time, New York date and time

ZonedDateTime zonedDateTimeNewYork = ZonedDateTime.now(ZoneId.of("America/New_York"));
System.out.println("纽约时区" + zonedDateTimeNewYork);
// 纽约时区 2021-11-25T19:34:05.929306-05:00[America/New_York]

Get the time in one time zone in another time zone

LocalDateTime ldt = LocalDateTime.of(2021, 6, 11, 23, 12, 24, 3000);
ZoneId zidShangHai = ZoneId.of("Asia/Shanghai");
ZonedDateTime zdtShangHai = ldt.atZone(zidShangHai);

ZoneId zidNewYork = ZoneId.of("America/New_York");
ZonedDateTime zdt_new_york = zdtShangHai.withZoneSameInstant(zidNewYork);

System.out.println(zdt_new_york);

ZonedDateTimeConversion

ZonedDateTime to long

ZonedDateTime zonedDateTime = ZonedDateTime.now();
long timestamps = zonedDateTime.toEpochSecond();
System.out.println("本地时间戳" + timestamps);
// 本地时间戳 1637887053

The timestamp represents the number of seconds from 0:00:00 in 1970 to the current time

toLocalDateTime
toLocalDate
toLocalTime

LocalDateTime to ZonedDateTime

LocalDateTime ldt = LocalDateTime.now();

ZonedDateTime zdt_local = ldt.atZone(ZoneId.systemDefault());
ZonedDateTime zdt_new_york = ldt.atZone(ZoneId.of("America/New_York"));

time adjustment

with

支持 LocalDateTime LocalDate LocalTime ZoneDateTime

withYear sets the specified year
withMonth sets the specified month
withDayOfMonth
withHour
withMinute
withSecond
withNano

Operation

Based on the current date and time, add the specified time, for example: plusYears(2)add 2 years

plusmeans increase, minusmeans decrease

plusYears() minusYears()Year
plusMonths() minusMonths()moon
plusDays() minusDays()Day
plusWeeks() minusWeeks()week
plusHours() minusHours()hour
plusMinutes() minusMinutes()point
plusSeconds() minusSeconds()Second
plusNanos() minusNanos()nanosecond

time slice

Period Duration inherits from, TemporalAmount represents a period of date and time; Period represents a period of date, Duration represents a period of time

Duration.ofDays(1)
Duration.ofHours(1)
…
Period.ofYears(1)
…

Operation

plus(TemporalAmount)Increase time slice
minus(TemporalAmount)Decrease time slice

LocalDateTime ldt = LocalDateTime.of(2021, 1, 12, 13, 24, 12);

Duration five_minute = Duration.ofMinutes(10);

LocalDateTime ldt_new = ldt.plus(five_minute);
// LocalDateTime ldt_new = ldt.minus(five_minute);
System.out.println(ldt_new);

// 2021-01-12T13:34:12

datetime string

time date format

ZonedDateTime zonedDateTime = ZonedDateTime.now();
String str_t = zonedDateTime.format(DateTimeFormatter.ofPattern("MM-dd-yyyy"));


Symbol  Meaning                     Presentation      Examples
------  -------                     ------------      -------
G       era                         text              AD; Anno Domini; A
y       year-of-era                 year              2004; 04
D       day-of-year                 number            189
M/L     month-of-year               number/text       7; 07; Jul; July; J
d       day-of-month                number            10
g       modified-julian-day         number            2451334
Q/q     quarter-of-year             number/text       3; 03; Q3; 3rd quarter
Y       week-based-year             year              1996; 96
w       week-of-week-based-year     number            27
W       week-of-month               number            4
E       day-of-week                 text              Tue; Tuesday; T
e/c     localized day-of-week       number/text       2; 02; Tue; Tuesday; T
F       day-of-week-in-month        number            3
a       am-pm-of-day                text              PM
h       clock-hour-of-am-pm (1-12)  number            12
K       hour-of-am-pm (0-11)        number            0
k       clock-hour-of-day (1-24)    number            24
H       hour-of-day (0-23)          number            0
m       minute-of-hour              number            30
s       second-of-minute            number            55
S       fraction-of-second          fraction          978
A       milli-of-day                number            1234
n       nano-of-second              number            987654321
N       nano-of-day                 number            1234000000
V       time-zone ID                zone-id           America/Los_Angeles; Z; -08:30
v       generic time-zone name      zone-name         Pacific Time; PT
z       time-zone name              zone-name         Pacific Standard Time; PST
O       localized zone-offset       offset-O          GMT+8; GMT+08:00; UTC-08:00
X       zone-offset 'Z' for zero    offset-X          Z; -08; -0830; -08:30; -083015; -08:30:15
x       zone-offset                 offset-x          +0000; -08; -0830; -08:30; -083015; -08:30:15
Z       zone-offset                 offset-Z          +0000; -0800; -08:00
p       pad next                    pad modifier      1

time zone table

<?xml version="1.0" encoding="UTF-8"?>
<timezones>
	<timezone id="Asia/Shanghai">中国标准时间 (北京)</timezone>
	<timezone id="Asia/Hong_Kong">香港时间 (香港)</timezone>
	<timezone id="Asia/Taipei">台北时间 (台北)</timezone>
	<timezone id="Asia/Seoul">首尔</timezone>
	<timezone id="Asia/Tokyo">日本时间 (东京)</timezone>
	<timezone id="America/New_York">美国东部时间 (纽约)</timezone>
	<timezone id="America/Denver">美国山区时间 (丹佛)</timezone>
	<timezone id="America/Costa_Rica">美国中部时间 (哥斯达黎加)</timezone>
    <timezone id="America/Chicago">美国中部时间 (芝加哥)</timezone>
    <timezone id="America/Mexico_City">美国中部时间 (墨西哥城)</timezone>
    <timezone id="America/Regina">美国中部时间 (里贾纳)</timezone>
    <timezone id="America/Los_Angeles">美国太平洋时间 (洛杉矶)</timezone>
    <timezone id="Pacific/Majuro">马朱罗</timezone>
    <timezone id="Pacific/Midway">中途岛</timezone>
    <timezone id="Pacific/Honolulu">檀香山</timezone>
    <timezone id="America/Anchorage">安克雷奇</timezone>
    <timezone id="America/Tijuana">美国太平洋时间 (提华纳)</timezone>
    <timezone id="America/Phoenix">美国山区时间 (凤凰城)</timezone>
    <timezone id="America/Chihuahua">奇瓦瓦</timezone>
    <timezone id="America/Bogota">哥伦比亚时间 (波哥大)</timezone>
    <timezone id="America/Caracas">委内瑞拉时间 (加拉加斯)</timezone>
    <timezone id="America/Barbados">大西洋时间 (巴巴多斯)</timezone>
    <timezone id="America/Manaus">亚马逊标准时间 (马瑙斯)</timezone>
    <timezone id="America/St_Johns">纽芬兰时间 (圣约翰)</timezone>
    <timezone id="America/Santiago">圣地亚哥</timezone>
    <timezone id="America/Argentina/Buenos_Aires">布宜诺斯艾利斯</timezone>
    <timezone id="America/Godthab">戈特霍布</timezone>
    <timezone id="America/Montevideo">乌拉圭时间 (蒙得维的亚)</timezone>
    <timezone id="America/Sao_Paulo">圣保罗</timezone>
    <timezone id="Atlantic/South_Georgia">南乔治亚</timezone>
    <timezone id="Atlantic/Azores">亚述尔群岛</timezone>
    <timezone id="Atlantic/Cape_Verde">佛得角</timezone>
    <timezone id="Africa/Casablanca">卡萨布兰卡</timezone>
    <timezone id="Europe/London">格林尼治标准时间 (伦敦)</timezone>
    <timezone id="Europe/Amsterdam">中欧标准时间 (阿姆斯特丹)</timezone>
    <timezone id="Europe/Belgrade">中欧标准时间 (贝尔格莱德)</timezone>
    <timezone id="Europe/Brussels">中欧标准时间 (布鲁塞尔)</timezone>
    <timezone id="Europe/Sarajevo">中欧标准时间 (萨拉热窝)</timezone>
    <timezone id="Africa/Brazzaville">西部非洲标准时间 (布拉扎维)</timezone>
    <timezone id="Africa/Windhoek">温得和克</timezone>
    <timezone id="Asia/Amman">东欧标准时间 (安曼)</timezone>
    <timezone id="Europe/Athens">东欧标准时间 (雅典)</timezone>
    <timezone id="Asia/Beirut">东欧标准时间 (贝鲁特)</timezone>
    <timezone id="Africa/Cairo">东欧标准时间 (开罗)</timezone>
    <timezone id="Europe/Helsinki">东欧标准时间 (赫尔辛基)</timezone>
    <timezone id="Asia/Jerusalem">以色列时间 (耶路撒冷)</timezone>
    <timezone id="Africa/Harare">中部非洲标准时间 (哈拉雷)</timezone>
    <timezone id="Europe/Minsk">明斯克</timezone>
    <timezone id="Asia/Baghdad">巴格达</timezone>
    <timezone id="Europe/Moscow">莫斯科</timezone>
    <timezone id="Asia/Kuwait">科威特</timezone>
    <timezone id="Africa/Nairobi">东部非洲标准时间 (内罗毕)</timezone>
    <timezone id="Asia/Tehran">伊朗标准时间 (德黑兰)</timezone>
    <timezone id="Asia/Baku">巴库</timezone>
    <timezone id="Asia/Tbilisi">第比利斯</timezone>
    <timezone id="Asia/Yerevan">埃里温</timezone>
    <timezone id="Asia/Dubai">迪拜</timezone>
    <timezone id="Asia/Kabul">阿富汗时间 (喀布尔)</timezone>
    <timezone id="Asia/Karachi">卡拉奇</timezone>
    <timezone id="Asia/Oral">乌拉尔</timezone>
    <timezone id="Asia/Yekaterinburg">叶卡捷林堡</timezone>
    <timezone id="Asia/Calcutta">加尔各答</timezone>
    <timezone id="Asia/Colombo">科伦坡</timezone>
    <timezone id="Asia/Katmandu">尼泊尔时间 (加德满都)</timezone>
    <timezone id="Asia/Almaty">阿拉木图</timezone>
    <timezone id="Asia/Rangoon">缅甸时间 (仰光)</timezone>
    <timezone id="Asia/Krasnoyarsk">克拉斯诺亚尔斯克</timezone>
    <timezone id="Asia/Bangkok">曼谷</timezone>
    <timezone id="Asia/Irkutsk">伊尔库茨克时间 (伊尔库茨克)</timezone>
    <timezone id="Asia/Kuala_Lumpur">吉隆坡</timezone>
    <timezone id="Australia/Perth">佩思</timezone>
    <timezone id="Asia/Yakutsk">雅库茨克时间 (雅库茨克)</timezone>
    <timezone id="Australia/Darwin">达尔文</timezone>
    <timezone id="Australia/Brisbane">布里斯班</timezone>
    <timezone id="Asia/Vladivostok">海参崴时间 (符拉迪沃斯托克)</timezone>
    <timezone id="Pacific/Guam">关岛</timezone>
    <timezone id="Australia/Adelaide">阿德莱德</timezone>
    <timezone id="Australia/Hobart">霍巴特</timezone>
    <timezone id="Australia/Sydney">悉尼</timezone>
    <timezone id="Asia/Magadan">马加丹时间 (马加丹)</timezone>
    <timezone id="Pacific/Auckland">奥克兰</timezone>
    <timezone id="Pacific/Fiji">斐济</timezone>
    <timezone id="Pacific/Tongatapu">东加塔布</timezone>
</timezones>