hutool时间工具类

数据库create_date数据格式为yyyyMMdd，图标统计需要查找日期等于最近7天的数据，条件如下

select * from xx_table where create_date >= smallDay and create_date <= maxDay;

获取时间集合方法如下

package com.zcjlq.hutool;

import cn.hutool.core.date.DateField;
import cn.hutool.core.date.DateTime;
import cn.hutool.core.date.DateUtil;

import java.util.Date;
import java.util.List;
import java.util.stream.Collectors;

public class DateUtilTest {
    public static void main(String[] args) {
        // 需求：获取最近n天日期，格式为yyyyMMdd的long集合
        List<String> daysList = getDaysList(-7);
        // 20231218
        //20231219
        //20231220
        //20231221
        //20231222
        //20231223
        //20231224
        daysList.forEach(System.out::println);
        
        String smallDay = daysList.get(0);
        String maxDay = daysList.get(daysList.size() - 1);
        System.out.printf("最小日期%s，最大日期%s%n", smallDay, maxDay);
        // select * from xx_table where create_date >= smallDay and create_date <= maxDay;
    }

    /**
     * 包含当日
     *
     * @param offset 偏移量
     * @return
     */
    private static List<String> getDaysList(int offset) {
        DateTime nDaysBefore = DateUtil.offsetDay(new Date(), offset + 1);
        List<DateTime> dateTimes = DateUtil.rangeToList(nDaysBefore, new Date(), DateField.DAY_OF_YEAR);
        List<String> yyyyMMdd = dateTimes.stream().map(a -> DateUtil.format(a, "yyyyMMdd")).collect(Collectors.toList());
        return yyyyMMdd;
    }
}