Java常用类07：JDK 1.8新特性日期时间类

LocalDate类

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class Hello{
    public static void main(String[] args) {
        //LocalDate.now()方法创建一个当前日期对象
        LocalDate d = LocalDate.now();
        System.out.println(d);  //2021-09-9，直接打印对象输出完整日期

        //对象的方法可以单独获取年、月、日、周几、一年的多少天
        System.out.println(d.getYear());  //2021
        System.out.println(d.getMonth());  //SEPTEMBER
        System.out.println(d.getMonthValue());  //9
        System.out.println(d.getDayOfMonth());  //9
        System.out.println(d.getDayOfWeek());  //SATURDAY
        System.out.println(d.getDayOfYear());  //260

        //LocalDate.of()方法可以创建一个自定义日期对象
        LocalDate yesterday = LocalDate.of(2021, 9, 8);
        System.out.println(yesterday);  //2021-09-08

        //isBefore()和isAfter()方法比较日期的先后
        System.out.println(d.isBefore(yesterday));

        //LocalDate.parse()方法创建一个格式化日期对象
        LocalDate date = LocalDate.parse("20210909", DateTimeFormatter.BASIC_ISO_DATE);
        System.out.println(date);  //2021-09-09
    }
}

LocalTime类

import java.time.LocalTime;

public class Hello{
    public static void main(String[] args) {
        //LocalTime.now()方法创建一个当前时间对象
        LocalTime t = LocalTime.now();
        System.out.println(t);  //18:58:44.195

        //对象的方法可以单独获取时、分、秒
        System.out.println(t.getHour());
        System.out.println(t.getMinute());
        System.out.println(t.getSecond());

        //LocalTime.of()方法可以创建一个自定义时间对象
        LocalTime past = LocalTime.of(20, 9, 8);
        System.out.println(past);  //20:09:08

        //isBefore()和isAfter()方法比较时间的先后
        System.out.println(t.isAfter(past));
    }
}