java8新特性 日期

1. LocalDateTime

2. Instant

package com.atguigu.java8;

import java.time.DayOfWeek;

import java.time.Duration;

import java.time.Instant;

import java.time.LocalDate;

import java.time.LocalDateTime;

import java.time.OffsetDateTime;

import java.time.Period;

import java.time.ZoneId;

import java.time.ZoneOffset;

import java.time.ZonedDateTime;

import java.time.format.DateTimeFormatter;

import java.time.temporal.TemporalAdjusters;

import java.util.Set;

import org.junit.Test;

public class TestLocalDateTime {

    //6.ZonedDate、ZonedTime、ZonedDateTime ： 带时区的时间或日期

    @Test

    public void test7(){

        LocalDateTime ldt = LocalDateTime.now(ZoneId.of("Asia/Shanghai"));

        System.out.println(ldt);

        ZonedDateTime zdt = ZonedDateTime.now(ZoneId.of("US/Pacific"));

        System.out.println(zdt);

    }

    @Test

    public void test6(){

        Set<String> set = ZoneId.getAvailableZoneIds();

        set.forEach(System.out::println);

    }

    //5. DateTimeFormatter : 解析和格式化日期或时间

    @Test

    public void test5(){

//        DateTimeFormatter dtf = DateTimeFormatter.ISO_LOCAL_DATE;

        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy年MM月dd日 HH:mm:ss E");

        LocalDateTime ldt = LocalDateTime.now();

        String strDate = ldt.format(dtf);

        System.out.println(strDate);

        LocalDateTime newLdt = ldt.parse(strDate, dtf);

        System.out.println(newLdt);

    }

    //4. TemporalAdjuster : 时间校正器

    @Test

    public void test4(){

    LocalDateTime ldt = LocalDateTime.now();

        System.out.println(ldt);

        LocalDateTime ldt2 = ldt.withDayOfMonth();

        System.out.println(ldt2);

        LocalDateTime ldt3 = ldt.with(TemporalAdjusters.next(DayOfWeek.SUNDAY));

        System.out.println(ldt3);

        //自定义：下一个工作日

        LocalDateTime ldt5 = ldt.with((l) -> {

            LocalDateTime ldt4 = (LocalDateTime) l;

            DayOfWeek dow = ldt4.getDayOfWeek();

            if(dow.equals(DayOfWeek.FRIDAY)){

                return ldt4.plusDays();

            }else if(dow.equals(DayOfWeek.SATURDAY)){

                return ldt4.plusDays();

            }else{

                return ldt4.plusDays();

            }

        });

        System.out.println(ldt5);

    }

    //3.

    //Duration : 用于计算两个“时间”间隔

    //Period : 用于计算两个“日期”间隔

    @Test

    public void test3(){

        Instant ins1 = Instant.now();

        System.out.println("--------------------");

        try {

            Thread.sleep();

        } catch (InterruptedException e) {

        }

        Instant ins2 = Instant.now();

        System.out.println("所耗费时间为：" + Duration.between(ins1, ins2));

        System.out.println("----------------------------------");

        LocalDate ld1 = LocalDate.now();

        LocalDate ld2 = LocalDate.of(, , );

        Period pe = Period.between(ld2, ld1);

        System.out.println(pe.getYears());

        System.out.println(pe.getMonths());

        System.out.println(pe.getDays());

    }

    //2. Instant : 时间戳。 （使用 Unix 元年  1970年1月1日 00:00:00 所经历的毫秒值）

    @Test

    public void test2(){

        Instant ins = Instant.now();  //默认使用 UTC 时区

        System.out.println(ins);

        OffsetDateTime odt = ins.atOffset(ZoneOffset.ofHours());

        System.out.println(odt);

        System.out.println(ins.getNano());

        Instant ins2 = Instant.ofEpochSecond();

        System.out.println(ins2);

    }

    //1. LocalDate、LocalTime、LocalDateTime

    @Test

    public void test1(){

        LocalDateTime ldt = LocalDateTime.now();

        System.out.println(ldt);

        LocalDateTime ld2 = LocalDateTime.of(, , , , , );

        System.out.println(ld2);

        LocalDateTime ldt3 = ld2.plusYears();

        System.out.println(ldt3);

        LocalDateTime ldt4 = ld2.minusMonths();

        System.out.println(ldt4);

        System.out.println(ldt.getYear());

        System.out.println(ldt.getMonthValue());

        System.out.println(ldt.getDayOfMonth());

        System.out.println(ldt.getHour());

        System.out.println(ldt.getMinute());

        System.out.println(ldt.getSecond());

    }

}

以上代码仅供学习参考使用