Java练习-----时间工具类（JDK8之后）

news2024/9/24 15:44:20

LocalDate/LocalTime/LocalDateTime类

ZoneDateTime和ZoneId

Instant类

DateTimeFormatter类：解析格式化时间

LocalDate/LocalTime/LocalDateTime类

package crrc.studytest1;

import java.time.Duration;
import java.time.LocalDateTime;

public class DurationClass {
    public static void main(String[] args) {
        //获取两个时间对象用来比较
        LocalDateTime start = LocalDateTime.of(1998,5,28,5,25,30);
        LocalDateTime end = LocalDateTime.of(2024,9,19,15,01,15);

        //创建一个Duration类来比较两个时间
        Duration duration = Duration.between(start,end);
        long days = duration.toDays();
        long hours = duration.toHours();
        long minutes = duration.toMinutes();
        long seconds = duration.getSeconds();
        long millis = duration.toMillis();
        long nanos = duration.toNanos();
        System.out.println(days);
        System.out.println(hours);
        System.out.println(minutes);
        System.out.println(seconds);
        System.out.println(millis);
        System.out.println(nanos);

    }
}

package crrc.studytest1;

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

public class LocalTimeClass {
    public static void main(String[] args) {
        //1.获取本地时间对象
        LocalTime ld = LocalTime.now();//时 分 秒 纳秒
        System.out.println(ld);

        //2.获取日期中的信息
        int hour = ld.getHour();//时
        int minute = ld.getMinute();//分
        int second = ld.getSecond();//秒
        int nano = ld.getNano();//纳秒
        System.out.println(hour);
        System.out.println(minute);
        System.out.println(second);
        System.out.println(nano);

        /*3.直接修改某个信息：withYear；withMonth.....都是以with开头，
        然后会返回一个新的对象，不会改变原有时间对象*/
        LocalTime ld2 = ld.withHour(15);
        System.out.println(ld2);
        LocalTime ld3 = ld2.withMinute(15);
        System.out.println(ld3);
        LocalTime ld33 = ld2.withSecond(0);
        System.out.println(ld33);

        //4.把某个信息加多少：plusYears；plusMonths；plusWeeks；
        LocalTime ld4 = ld.plusHours(10);
        System.out.println(ld4);
        LocalTime ld5 = ld.plusMinutes(10);
        System.out.println(ld5);

        //5.把某个信息减多少：minusYears；minusMonths；minusWeeks；minusDays；
        LocalTime ld6 = ld.minusHours(10);
        System.out.println(ld6);
        LocalTime ld7 = ld.minusSeconds(10);
        System.out.println(ld7);

        //6.获取指定日期的LocalDate对象：public static LocalDate of(int year,int month,int day)
        LocalTime ld8 = LocalTime.of(10,5,28);
        LocalTime ld9 = LocalTime.of(13,5,18);
        LocalTime ld10 = LocalTime.of(13,5,18);
        System.out.println(ld8);
        System.out.println(ld9);
        System.out.println(ld10);

        //7.判断两个日期对象，是否相等，在前还是在后： equals；isBefore；isAfter；
        System.out.println(ld9.equals(ld10));
        System.out.println(ld9.equals(ld8));
        System.out.println(ld8.isAfter(ld9));
        System.out.println(ld8.isBefore(ld9));
    }
}

package crrc.studytest1;

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

public class LocalDateTimeClass {
    public static void main(String[] args) {
        //用法基本和前面两个类一样 只不过把他们结合起来了 在这儿不演示了
        //简单用一下他们三者之间的转换
        LocalTime lt = LocalTime.now();
        LocalDate ld = LocalDate.now();
        LocalDateTime ldt = LocalDateTime.of(ld,lt);
        LocalDateTime ldt1 = LocalDateTime.now();
        LocalTime lt1 = ldt1.toLocalTime();
        LocalDate ld1 = ldt1.toLocalDate();
        System.out.println(lt);
        System.out.println(ld);
        System.out.println(ldt);
        System.out.println(ldt1);
        System.out.println(lt1);
        System.out.println(ld1);
    }
}

ZoneDateTime和ZoneId

package crrc.studytest1;

import java.time.Clock;
import java.time.ZoneId;
import java.time.ZonedDateTime;

public class ZoneId_ZoneDateTime {
    public static void main(String[] args) {
        //获取当前系统的时区id并打印出来
        // public static ZoneId systemDefault():获取系统默认时区
        ZoneId zoneId = ZoneId.systemDefault();
        System.out.println(zoneId);
        System.out.println(zoneId.getId());

        //获取Java支持的所有时区ID
        System.out.println(ZoneId.getAvailableZoneIds());

        //把某个时区ID封装成 ZoneId对象
        ZoneId zoneId1 = ZoneId.of("America/New_York");

        //ZoneDateTime 带时区的时间
        //public static ZoneDateTime now(ZoneId zone):获取某个时区的ZoneDateTime对象
        ZonedDateTime nowUSA = ZonedDateTime.now(zoneId1);
        ZonedDateTime nowChina = ZonedDateTime.now(zoneId);
        System.out.println(nowUSA);
        System.out.println(nowChina);

        //世界标准时间
        ZonedDateTime now = ZonedDateTime.now(Clock.systemUTC());
        System.out.println(now);

        //默认系统时间
        ZonedDateTime now2 = ZonedDateTime.now();
        System.out.println(now2);
    }
}

Instant类

package crrc.studytest1;

import java.time.Instant;

public class InstantClass {
    public static void main(String[] args) {
        //一般用来做代码性能分析 在代码执行前和代码执行后分别获取此刻时间戳，相减就是代码运行时间
        Instant instant = Instant.now();
        System.out.println(instant);

        //获取总秒数
        long second = instant.getEpochSecond();
        //获取不够1秒的纳秒数
        long nano = instant.getNano();
        System.out.println(second);
        System.out.println(nano);

        //也有plus minus 等方法 返回一个新的Instant对象
    }
}

DateTimeFormatter类：解析格式化时间

package crrc.studytest1;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class DateTimeFormatterClass {
    public static void main(String[] args) {
        //用于时间格式化解析的
        //1.创建一个日期时间格式化对象器出来
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

        //2.准备一些时间对其进行格式化
        LocalDateTime ldt = LocalDateTime.now();
        System.out.println(ldt);
        String strTime = dtf.format(ldt);//时间格式变成字符串(正向格式化)
        System.out.println(strTime);
        String strTime1 = ldt.format(dtf);//也可以用LocalDateTime类提供的format方法进行转换需要传入格式化器（反向格式化）
        System.out.println(strTime1);

        //3.解析时间 将字符串类型时间转换成相应时间对象
        String dateStr = "1998年5月28日 18:55:36";
        DateTimeFormatter dtf1 = DateTimeFormatter.ofPattern("yyyy年M月dd日 HH:mm:ss");
        LocalDateTime ldt1 = LocalDateTime.parse(dateStr,dtf1);
        System.out.println(ldt1);

    }
}

Period类

package crrc.studytest1;

import java.time.LocalDate;
import java.time.Period;

public class PeriodClass {
    public static void main(String[] args) {
        //1.先准备两个时间对象用于计算二者的时间间隔
        LocalDate ld1 = LocalDate.now();
        LocalDate ld2 = ld1.plusMonths(13);
        LocalDate ld3 = ld2.plusYears(5);
        LocalDate ld4 = ld3.plusDays(20);
        System.out.println(ld1);
        System.out.println(ld4);
        //2.创建一个Period对象
        Period p = Period.between(ld1,ld4);

        //3.获取两个日期相差的信息
        int year = p.getYears();
        int month = p.getMonths();
        int day = p.getDays();
        System.out.println(year);
        System.out.println(month);
        System.out.println(day);

    }
}

Duration类

package crrc.studytest1;

import java.time.Duration;
import java.time.LocalDateTime;

public class DurationClass {
    public static void main(String[] args) {
        //获取两个时间对象用来比较
        LocalDateTime start = LocalDateTime.of(1998,5,28,5,25,30);
        LocalDateTime end = LocalDateTime.of(2024,9,19,15,01,15);

        //创建一个Duration类来比较两个时间
        Duration duration = Duration.between(start,end);
        long days = duration.toDays();
        long hours = duration.toHours();
        long minutes = duration.toMinutes();
        long seconds = duration.getSeconds();
        long millis = duration.toMillis();
        long nanos = duration.toNanos();
        System.out.println(days);
        System.out.println(hours);
        System.out.println(minutes);
        System.out.println(seconds);
        System.out.println(millis);
        System.out.println(nanos);

    }
}