Date、LocalDate、LocalDateTime、LocalTime互相转换

参考：https://blog.csdn.net/weixin_55365140/article/details/118219902

package com.lch.time;
import java.time.*;
import java.time.format.DateTimeFormatter;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjusters;
import java.util.Date;
/**
 * 时间转换
 */
public class TimeConvert {
    public static void main(String[] args) {
        //获取指定时间（年月日）
        LocalDate appointTime = LocalDate.of(2022, 1, 1);
        //获取现在的时间（年月日）
        LocalDate nowTime = LocalDate.now();
        //获取某日期是当周星期几（枚举类型）
        DayOfWeek dayOfWeek = nowTime.getDayOfWeek();
        //获取某日期是当年的第几天
        int dayOfYear = nowTime.getDayOfYear();
        //获取某日期是当月的几号
        int dayOfMonth = nowTime.getDayOfMonth();
        //获取年
        int year = nowTime.getYear();
        //获取月份对象（枚举） 如 ：四月APRIL
        Month month = nowTime.getMonth();
        //获取月的值
        int monthValue = nowTime.getMonthValue();
        //加N天
        LocalDate localDate = nowTime.plusDays(1);
        //加N星期
        LocalDate localDate1 = nowTime.plusWeeks(1);
        //加N月
        LocalDate localDate2 = nowTime.plusMonths(1);
        //加N年
        LocalDate localDate3 = nowTime.plusYears(1);
        //减n天
        LocalDate localDate4 = nowTime.minusDays(1);
        //减n周
        LocalDate localDate5 = nowTime.minusWeeks(1);
        //减n月
        LocalDate localDate6 = nowTime.minusMonths(1);
        //减n年
        LocalDate localDate7 = nowTime.minusYears(1);
        //获取两个日期之间的间隔
        Period period = Period.between(LocalDate.of(2021, 6, 24), LocalDate.of(2021, 5, 24));
        //获取两个日期相差的天数
        int days = period.getDays();
        //获取两个日期相差的月
        int months = period.getMonths();
        //获取两个日期相差的年
        int years = period.getYears();

Date 与 LocalDate 转换

        /**
         * Date 转成 LocalDate
         */
        LocalDate localDate = new Date()
                            .toInstant()
                            .atZone(ZoneId.systemDefault())
                            .toLocalDate();
        /**
         * LocalDate 转成 Date
         */
        Date date2 = Date.from(
                         LocalDate.now()
                         .atStartOfDay(ZoneId.systemDefault())
                         .toInstant()
                     );

Date 与 LocalTime 转换

        /**
         * Date 转成 LocalTime
         */
        LocalTime localTime = new Date()
                            .toInstant()
                            .atZone(ZoneId.systemDefault())
                            .toLocalTime();            
        /**
         * LocalTime 转成 Date
         */
        Date date1 = Date.from(
                        LocalDateTime.of(LocalDate.now(), LocalTime.now())
                        .atZone(ZoneId.systemDefault())
                        .toInstant()
                    );
     }
}