java8日期计算（偏移N周，返回指定星期的日期）

package com.example.demo;
 
import java.time.DayOfWeek;
import java.time.LocalDate;
 
public class MyDataTimeUtil {
    /**
     * 获取前n个月
     * @param n 数值
     * @param localDate 比较时间
     * @return
     */
    public static LocalDate getLastMonth(LocalDate localDate, int n) {
        return localDate.minusMonths(n);
    }
 
    /**
     * 获取后n个月
     * @param n 数值
     * @param localDate 比较时间
     * @return
     */
    public static LocalDate getNextMonth(LocalDate localDate, int n) {
        return localDate.plusMonths(n);
    }
 
    /**
     * 获取前n个月
     * @param n 数值
     * @return
     */
    public static LocalDate getLastMonth(int n) {
        return getLastMonth(LocalDate.now(), n);
    }
 
    /**
     * 获取后n个月
     * @param n 数值
     * @return
     */
    public static LocalDate getNextMonth(int n) {
        return getNextMonth(LocalDate.now(), n);
    }
 
    /**
     * 获取开始时间的dayOfWeek的日期
     * @param localDate 开始时间
     * @param dayOfWeek 周几
     * @return 日期
     */
    public static LocalDate getCurrentWeekMonday(LocalDate localDate,DayOfWeek dayOfWeek) {
        int weekValue = localDate.getDayOfWeek().getValue();
        int paramWeekValue = dayOfWeek.getValue();
        if (weekValue == paramWeekValue) {
            return localDate;
        }
        if(paramWeekValue>weekValue){
          return   localDate.plusDays(paramWeekValue - weekValue);
        }else {
            return   localDate.minusDays(weekValue - paramWeekValue);
        }
    }
 
    /**
     * 获取当前时间的dayOfWeek的日期
     * @param dayOfWeek 周几
     * @return 日期
     */
    public static LocalDate getCurrentWeekMonday(DayOfWeek dayOfWeek) {
        return getCurrentWeekMonday(LocalDate.now(),dayOfWeek);
    }
 
 
 
    /**
     * 获取开始时间的dayOfWeek的日期
     * @param localDate 开始时间
     * @param dayOfWeek 周几
     * @param n n周前
     * @return
     */
    public static LocalDate getLastWeekMonday(LocalDate localDate,DayOfWeek dayOfWeek,int n) {
        localDate = localDate.minusDays(n*7);
        return getCurrentWeekMonday(localDate,dayOfWeek);
    }
 
    /**
     * 获取当前时间的dayOfWeek的日期
     * @param dayOfWeek 周几
     * @param n n周前
     * @return
     */
    public static LocalDate getLastWeekMonday(DayOfWeek dayOfWeek,int n) {
        LocalDate localDate = LocalDate.now().minusDays(n*7);
        return getCurrentWeekMonday(localDate,dayOfWeek);
    }
 
    /**
     * 获取开始时间的dayOfWeek的日期
     * @param localDate 开始时间
     * @param dayOfWeek 周几
     * @param n n周后
     * @return
     */
    public static LocalDate getNextWeekMonday(LocalDate localDate,DayOfWeek dayOfWeek,int n) {
        localDate = localDate.plusDays(n*7);
        return getCurrentWeekMonday(localDate,dayOfWeek);
    }
 
    /**
     * 获取开始时间的dayOfWeek的日期
     * @param dayOfWeek 周几
     * @param n n周后
     * @return
     */
    public static LocalDate getNextWeekMonday(DayOfWeek dayOfWeek,int n) {
        LocalDate localDate = LocalDate.now().plusDays(n*7);
        return getCurrentWeekMonday(localDate,dayOfWeek);
    }
}

 public static void main(String[] args) {
        //日期
        LocalDate localDate = LocalDate.of(2022,8,26);
        //当前日期 2022-08-26
        System.out.println(localDate);
        //2022-08-26是那一年 2022
        System.out.println(localDate.getYear());
        //2022-08-26的月份 8
        System.out.println(localDate.getMonth().getValue());
        //2022-08-26是本月的第几天 26
        System.out.println(localDate.getDayOfMonth());
        //2022-08-26是周几 5
        System.out.println(localDate.getDayOfWeek().getValue());
        //2022-08-26是当年的第多少天 238
        System.out.println(localDate.getDayOfYear());
        System.out.println("------------");
        //获取2022-8-22前一个月 7
        System.out.println(MyDataTimeUtil.getLastMonth(localDate,1).getMonthValue());
        //获取2022-8-22后一个月 9
        System.out.println(MyDataTimeUtil.getNextMonth(localDate,1).getMonthValue());
        //获取2022-8-22，所在周的周一 2022-08-22
        System.out.println(MyDataTimeUtil.getCurrentWeekMonday(localDate,DayOfWeek.MONDAY));
        //获取2022-8-22，两周前的周五 2022-08-12
        System.out.println(MyDataTimeUtil.getLastWeekMonday(localDate,DayOfWeek.FRIDAY,2));
        //获取2022-8-22，一周后的周一 2022-08-29
        System.out.println(MyDataTimeUtil.getNextWeekMonday(localDate,DayOfWeek.MONDAY,1));
    }