【JAVA8新的时间与日期 API】- 本地时间(LocalDate、 LocalTime、 LocalDateTime)与时间戳(Instant)

LocalDate、 LocalTime、 LocalDateTime

LocalDate、 LocalTime、 LocalDateTime 类的实例是 不可变对象 ,分表表示使用 ISO-8601 日历系统的日期、时间、日期和时间。他们提供了简单的日期或时间,并不包含当前的时间信息。也不包含与时区相关的信息。

注:ISO-8601 日历系统是国际标准化组织制定的现代公民的日期和时间的表示法。说白了就是全球统一标准的表示方法。

【JAVA8新的时间与日期 API】- 本地时间(LocalDate、 LocalTime、 LocalDateTime)与时间戳(Instant)

 

 示例1:

import org.junit.Test;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.Month;

public class TestLocalDateTime {
    @Test
    public void test1(){
        LocalDate localDate = LocalDate.now();
        System.out.println(localDate);//输出:2020-06-25
        LocalTime localTime = LocalTime.now();
        System.out.println(localTime);//输出:23:12:59.211
        LocalDateTime localDateTime = LocalDateTime.now();
        System.out.println(localDateTime);//输出:2020-06-25T23:12:59.211
        System.out.println("-------------------------------------------");
        localDate = LocalDate.of(2022,1,1);
        System.out.println(localDate);//输出:2022-01-01
        localDate = LocalDate.of(2023, Month.AUGUST,2);
        System.out.println("-------------------------------------------");
        System.out.println(localDate);//输出:2023-08-02
        localTime = LocalTime.of(1,2);
        System.out.println(localTime);//输出:01:02
        localTime = LocalTime.of(1,2,3);
        System.out.println(localTime);//输出:01:02:03
        localTime = LocalTime.of(1,2,3,4);
        System.out.println(localTime);//输出:01:02:03.000000004
        System.out.println("-------------------------------------------");
        localDateTime = LocalDateTime.of(localDate,localTime);
        System.out.println(localDateTime);//输出:2023-08-02T01:02:03.000000004
        localDateTime = LocalDateTime.of(2024,1,1,1,1);
        System.out.println(localDateTime);//输出:2024-01-01T01:01
        localDateTime = LocalDateTime.of(2024,1,1,1,1,1);
        System.out.println(localDateTime);//输出:2024-01-01T01:01:01
        localDateTime = LocalDateTime.of(2024,1,1,1,1,1,1);
        System.out.println(localDateTime);//输出:2024-01-01T01:01:01.000000001
        localDateTime = LocalDateTime.of(2024,Month.of(2),1,1,1,1,1);
        System.out.println(localDateTime);//输出:2024-02-01T01:01:01.000000001
    }
} 

示例2:

 @Test
    public void test2(){
        LocalDate localDate = LocalDate.now();
        System.out.println(localDate);//输出:2020-06-30
        localDate = localDate.plusYears(1);
        System.out.println(localDate);//输出:2021-06-30
        localDate = localDate.plusMonths(2);
        System.out.println(localDate);//输出:2021-08-30
        localDate = localDate.plusDays(3);
        System.out.println(localDate);//输出:2021-09-02
        localDate = localDate.plusWeeks(4);
        System.out.println(localDate);//输出:2021-09-30
        localDate = localDate.plus(Period.ofDays(10));//加10天
        System.out.println(localDate);//输出:2021-10-10
        localDate = localDate.plus(Period.of(1,2,3));//加一年两个月三天
        System.out.println(localDate);//输出:2022-12-13
        localDate = localDate.plus(Period.ofYears(2));//加两年
        System.out.println(localDate);//输出:2024-12-13
        localDate = localDate.plus(1, ChronoUnit.DAYS);//加一天
        System.out.println(localDate);//输出:2024-12-14
        localDate = localDate.plus(1, ChronoUnit.MONTHS);//加一个月
        System.out.println(localDate);//输出:2025-01-14
        System.out.println("-------------------------------------------");
        localDate = localDate.minusYears(1);
        System.out.println(localDate);//输出:2024-01-14
        localDate.minusMonths(1);
        localDate.minusDays(1);
        localDate.minusWeeks(1);
        localDate.minus(Period.ofYears(2));
        //..........其他用法和plus一样...........
        System.out.println("-------------------------------------------");

        LocalTime localTime = LocalTime.now();
        System.out.println(localTime);//输出:21:35:54.776
        localTime = localTime.plusHours(1);
        System.out.println(localTime);//输出:22:35:54.776
        //..........其他用法和localDate的一样...........
        //..........LocalDateTime的用法也一样...........
    }

示例3:

    @Test
    public void test3(){
        LocalDate localDate = LocalDate.now();
        System.out.println(localDate);//输出:2020-06-30
        System.out.println(localDate.getYear());//输出:2020
        System.out.println(localDate.getDayOfMonth());//输出:30
        //..........等.......

        //将天数、月份、等修改为指定的值
        localDate = localDate.withDayOfMonth(22);
        System.out.println(localDate);//输出:2020-06-22
        localDate = localDate.withMonth(11);
        System.out.println(localDate);//输出:2020-11-22
        localDate = localDate.with(LocalDate.now());
        System.out.println(localDate);//输出:2020-06-30
        //..........等.......
        System.out.println("-------------------------------------------");

        Period period = localDate.until(LocalDate.of(2020, 1, 1));
        System.out.println(period.get(ChronoUnit.YEARS));//输出:0  相差 0 年
        System.out.println(period.get(ChronoUnit.MONTHS));//输出:-5  相差 1 - 6 = -5 月
        System.out.println(period.get(ChronoUnit.DAYS));//输出:-29  相差 1 - 30 = -29 天
        System.out.println("-------------------------------------------");

        System.out.println(localDate.isAfter(LocalDate.of(2020, 1, 1))); //输出:true
        System.out.println(localDate.isBefore(LocalDate.of(2020, 1, 1))); //输出:false
        System.out.println(localDate.isLeapYear());//是否闰年,输出:true
    }

 

Instant 时间戳

 时间戳,以 Unix 元年:1970年1月1日00:00:00 到某个时间之间的毫秒值 。

示例:

    @Test
    public void test4() {
        Instant ins1 = Instant.now();    // 默认获取UTC时区(世界协调时间,基本上是美国鬼子使用,和中国时间相差大概8小时)
        System.out.println(ins1);//输出结果:2020-06-30T14:28:05.217Z

        // 偏移量运算
        OffsetDateTime offsetDateTime = ins1.atOffset(ZoneOffset.ofHours(8));
        System.out.println(offsetDateTime);// 输出结果:2020-06-30T22:28:05.217+08:00    当前系统时间,国际标准的显示时间方式

        // 获取时间戳
        System.out.println(ins1.toEpochMilli());//输出结果:1593527285217

        // 以Unix元年为起点,进行偏移量运算
        Instant ins2 = Instant.ofEpochSecond(60);
        System.out.println(ins2);// 运行结果:1970-01-01T00:01:00Z
    }

 

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