Java之工作日的计算

业务开发中，若要求获取下一个工作日或上一个工作日，则可使用以下Java类。

package com.cmit.kapok.system.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.time.DayOfWeek;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;

/**
 * @Title: 计算时间周期之间工作日的时间
 * #Description: CalcWorkDaysUtil
 * #Date: 2022/6/2 14:42
 */
public class CalcWorkDaysUtil {
    private Logger logger = LoggerFactory.getLogger(CalcWorkDaysUtil.class);
    // 定义2个List用于存储特殊的工作日和非工作日
    // 特别的工作日（周六，周日上班的日期集合）
    private static List<String> SPECIAL_WORK_DAYS = new ArrayList<>();

    // 特别的休息日（周一到周五休息的日期集合）
    private static List<String> SPECIAL_OFF_DAYS = new ArrayList<>();

    // 在这里我就使用静态将2022年所有的节假日存到相应的list中
    // 大多是都是从数据库中获取的（这里就这样演示，大家后期可以从数据库获取）
    static {
        // 特殊的工作日（周六、周日上班的日期集合）
        SPECIAL_WORK_DAYS.add("2022-01-29");
        SPECIAL_WORK_DAYS.add("2022-01-30");
        SPECIAL_WORK_DAYS.add("2022-04-02");
        SPECIAL_WORK_DAYS.add("2022-04-24");
        SPECIAL_WORK_DAYS.add("2022-05-07");
        SPECIAL_WORK_DAYS.add("2022-10-08");
        SPECIAL_WORK_DAYS.add("2022-10-09");

        // 特殊的休息日（周一到周五休息的日期集合）
        SPECIAL_OFF_DAYS.add("2022-01-01");
        SPECIAL_OFF_DAYS.add("2022-01-02");
        SPECIAL_OFF_DAYS.add("2022-01-03");
        SPECIAL_OFF_DAYS.add("2022-01-31");
        SPECIAL_OFF_DAYS.add("2022-02-01");
        SPECIAL_OFF_DAYS.add("2022-02-02");
        SPECIAL_OFF_DAYS.add("2022-02-03");
        SPECIAL_OFF_DAYS.add("2022-02-04");
        SPECIAL_OFF_DAYS.add("2022-02-05");
        SPECIAL_OFF_DAYS.add("2022-02-06");
        SPECIAL_OFF_DAYS.add("2022-04-03");
        SPECIAL_OFF_DAYS.add("2022-04-04");
        SPECIAL_OFF_DAYS.add("2022-04-05");
        SPECIAL_OFF_DAYS.add("2022-04-30");
        SPECIAL_OFF_DAYS.add("2022-05-01");
        SPECIAL_OFF_DAYS.add("2022-05-02");
        SPECIAL_OFF_DAYS.add("2022-05-03");
        SPECIAL_OFF_DAYS.add("2022-05-04");
        SPECIAL_OFF_DAYS.add("2022-06-03");
        SPECIAL_OFF_DAYS.add("2022-06-04");
        SPECIAL_OFF_DAYS.add("2022-06-05");
        SPECIAL_OFF_DAYS.add("2022-09-10");
        SPECIAL_OFF_DAYS.add("2022-09-11");
        SPECIAL_OFF_DAYS.add("2022-09-12");
        SPECIAL_OFF_DAYS.add("2022-10-01");
        SPECIAL_OFF_DAYS.add("2022-10-01");
        SPECIAL_OFF_DAYS.add("2022-10-02");
        SPECIAL_OFF_DAYS.add("2022-10-03");
        SPECIAL_OFF_DAYS.add("2022-10-04");
        SPECIAL_OFF_DAYS.add("2022-10-05");
        SPECIAL_OFF_DAYS.add("2022-10-06");
        SPECIAL_OFF_DAYS.add("2022-10-07");
    }

    // 日期格式化方法（非线程安全的，可根据情况在方法内使用，或使用DateTimeFormatter）
    private static DateTimeFormatter SDF =  DateTimeFormatter.ofPattern("yyyy-MM-dd");

    private static DateTimeFormatter SDFS = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

    public static LocalDateTime nextWorkDay(LocalDateTime dateTime){
        LocalDateTime modifiedDate = dateTime.plusDays(1);
        DayOfWeek week = modifiedDate.getDayOfWeek();
        String dateStr = modifiedDate.format(SDF);
        //如果是周末，但是是特别工作日
        if((week.equals(DayOfWeek.SATURDAY) || week.equals(DayOfWeek.SUNDAY)) && SPECIAL_WORK_DAYS.contains(dateStr)){
            return modifiedDate;
        }else if(!week.equals(DayOfWeek.SATURDAY) && !week.equals(DayOfWeek.SUNDAY) && !SPECIAL_OFF_DAYS.contains(dateStr)){
            return modifiedDate;
        }else{
            return nextWorkDay(modifiedDate);
        }
    }

    public static LocalDateTime nextWorkDay(LocalDateTime dateTime,Integer num){
        if(num<1){
            return dateTime;
        }
        while(num>0){
            dateTime = nextWorkDay(dateTime);
            num--;
        }
        return dateTime ;
    }

    public static LocalDateTime lastWorkDay(LocalDateTime dateTime){
        LocalDateTime modifiedDate = dateTime.minusDays(1);
        DayOfWeek week = modifiedDate.getDayOfWeek();
        String dateStr = modifiedDate.format(SDF);
        //如果是周末，但是是特别工作日
        if((week.equals(DayOfWeek.SATURDAY) || week.equals(DayOfWeek.SUNDAY)) && SPECIAL_WORK_DAYS.contains(dateStr)){
            return modifiedDate;
        }else if(!week.equals(DayOfWeek.SATURDAY) && !week.equals(DayOfWeek.SUNDAY) && !SPECIAL_OFF_DAYS.contains(dateStr)){
            return modifiedDate;
        }else{
            return lastWorkDay(modifiedDate);
        }
    }

    public static LocalDateTime lastWorkDay(LocalDateTime dateTime,Integer num){
        if(num<1){
            return dateTime;
        }
        while(num>0){
            dateTime = lastWorkDay(dateTime);
            num--;
        }
        return dateTime ;
    }

    public static void main(String[] args) {
        LocalDateTime input = LocalDateTime.of(2022,11,28,12,12);
        LocalDateTime dateTime = lastWorkDay(input);
        System.out.println(dateTime);
    }
}