LocalDate和LocalTime和LocalDateTime基本用法

灰太狼 2023-09-27 20:25 24阅读 0赞

package com.test.test02;
    
    import java.time.LocalDate;
    import java.time.LocalDateTime;
    import java.time.LocalTime;
    import java.util.Calendar;
    import java.util.Scanner;
    
    public class Test09 {
        //这是一个main方法，是程序的入口
        public static void main(String[] args) {
            // 1.完成实例化
            //方法1：now()
            LocalDate localDate = LocalDate.now();
            System.out.println(localDate);
            LocalTime localTime = LocalTime.now();
            System.out.println(localTime);
            LocalDateTime localDateTime = LocalDateTime.now();
            System.out.println(localDateTime);
    
            /*
            *   2023-05-09
                11:15:12.442
                2023-05-09T11:15:12.442
            * */
    
            //方法2：of()--设置指定的日期，时间，日期+时间
            LocalDate of = LocalDate.of(2023, 05, 10);
            System.out.println(of);
            LocalTime of1 = LocalTime.of(11, 18, 16, 9);
            System.out.println(of1);
            LocalDateTime of2 = LocalDateTime.of(2023, 05, 9, 11, 19, 22);
            System.out.println(of2);
    
            /*
            *   2023-05-10
                11:18:16.000000009
                2023-05-09T11:19:22
            *
            * */
    
            //LocalDate LocalTime用的不如LocalDateTime多。
            //LocalDateTime  get
            System.out.println(localDateTime.getYear());//2023
            System.out.println(localDateTime.getMonth());//MAY
            System.out.println(localDateTime.getMonthValue());//5
            System.out.println(localDateTime.getDayOfMonth());//9
            System.out.println(localDateTime.getDayOfWeek());//TUESDAY
            System.out.println(localDateTime.getHour());//11
            System.out.println(localDateTime.getMinute());//24
            System.out.println(localDateTime.getSecond());//40
    
            /*
            *   2023
                MAY
                5
                9
                TUESDAY
                11
                24
                40
            *
            *
            * */
            //不是set方法，叫with
            //体会：不可变性
            LocalDateTime localDateTime2 = localDateTime.withMonth(6);
            System.out.println(localDateTime);//2023-05-09T11:34:54.114
            System.out.println(localDateTime2);//2023-06-09T11:34:54.114
    
            //提供了加减的操作
            //加
            LocalDateTime localDateTime1 = localDateTime.plusMonths(4);
            System.out.println(localDateTime); //2023-05-09T13:49:34.699
            System.out.println(localDateTime1);//2023-09-09T13:49:34.699
    
            //减
            LocalDateTime localDateTime3 = localDateTime.minusMonths(3);
            System.out.println(localDateTime); //2023-05-09T13:58:24.149
            System.out.println(localDateTime3);//2023-02-09T13:54:29.734
        }
    }