Java 万年历、周六日计算、节假日导出

news2024/10/1 19:23:29

通过 Java 的基本语法来实现万年历

Java 获取一年中所有的周六和周日

Java 节假日导入导出

通过 Java 的基本语法来实现万年历

在 Java 的时间计算方面还有很多好用的工具类，Java 常用的工具类封装框架链接如下：HUTool 框架官网

package com.taier.pulsar.date_utils;

import java.util.Scanner;

/**
 * @author swadian2008
 */
public class DateUtils {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入年：");
        int year = sc.nextInt();
        System.out.println("请输入月份：");
        int month = sc.nextInt();
        //1.计算1900.1.1到输入年的天数
        int dayOfYear = 0;
        for (int i = 1900; i < year; i++) {
            if (i % 4 == 0 && i % 100 != 0 || i % 400 == 0) { // 闰年
                dayOfYear += 366;
            } else {
                dayOfYear += 365;
            }
        }
        //2.计算1月到输入月的天数
        int dayOfMonth = 0;
        for (int i = 1; i < month; i++) {
            switch (i) {
                case 1:
                case 3:
                case 5:
                case 7:
                case 8:
                case 10:
                case 12:
                    dayOfMonth += 31;
                    break;
                case 4:
                case 6:
                case 9:
                case 11:
                    dayOfMonth += 30;
                    break;
                case 2:
                    if ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)) {
                        dayOfMonth += 29;
                    } else {
                        dayOfMonth += 28;
                    }
                    break;
            }
        }
        //3.获取输入月的天数
        int day = 0;
        switch (month) {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
                day = 31;
                break;
            case 4:
            case 6:
            case 9:
            case 11:
                day = 30;
                break;
            case 2:
                if ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)) {
                    day = 29;
                } else {
                    day = 28;
                }
                break;
        }
        //4.计算星期
        int allDay = dayOfYear + dayOfMonth + 1;
        int week = allDay % 7; // 计算余数在星期中的位置
        int count = 0;// 计数器,记录日期的空格

        System.out.println("星期日\t星期一\t星期二\t星期三\t星期四\t星期五\t星期六");
        //5.打印空格
        for (int i = 1; i <= week; i++) {
            System.out.print("\t\t\t");
            count++;
        }
        //6. 打印日历
        for (int i = 1; i <= day; i++) {
            if (i < 10) { // 为了格式化
                System.out.print(i + "\t\t\t");
            } else {
                System.out.print(i + "\t\t");
            }
            count++;
            //若记录数是七的倍数，换行输出
            if (count % 7 == 0) {
                System.out.println();
            }
        }
    }
}

打印效果如下：

Java 获取一年中所有的周六和周日

下边的示例中使用了一个Map来收集周六和周日，可以根据需要进行调节：

import static java.time.temporal.TemporalAdjusters.firstInMonth;
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.Month;
import java.time.Period;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.stream.Collectors;
import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;

/**
 * @author swadian2008
 */
public class WeekDay {

    public static void main(String[] args) {
        // 创建代表一年中第一天的LocalDate对象。
        int year = 2023;
        LocalDate now = LocalDate.of(year, Month.JANUARY, 1);
        Map<String, List<Integer>> weekMap = new HashMap<>(12);
        // 第一个星期六
        LocalDate saturday = now.with(firstInMonth(DayOfWeek.SATURDAY));
        do {
            String satMonth = String.valueOf(saturday.getMonthValue());
            if (CollectionUtils.isEmpty(weekMap.get(satMonth))) {
                weekMap.put(satMonth, new ArrayList<>(Arrays.asList(saturday.getDayOfMonth())));
            } else {
                List<Integer> values = weekMap.get(satMonth);
                values.add(saturday.getDayOfMonth());
                Collections.sort(values);
                weekMap.put(satMonth, values);
            }
            // 迭代一个星期
            saturday = saturday.plus(Period.ofDays(7));
        } while (saturday.getYear() == year);
        // 第一个星期天
        LocalDate sunday = now.with(firstInMonth(DayOfWeek.SUNDAY));
        do {
            String sunMonth = String.valueOf(sunday.getMonthValue());
            if (CollectionUtils.isEmpty(weekMap.get(sunMonth))) {
                weekMap.put(sunMonth, new ArrayList<>(Arrays.asList(sunday.getDayOfMonth())));
            } else {
                List<Integer> values = weekMap.get(sunMonth);
                values.add(sunday.getDayOfMonth());
                Collections.sort(values);
                weekMap.put(sunMonth, values);
            }
            // 迭代一个星期
            sunday = sunday.plus(Period.ofDays(7));
        } while (sunday.getYear() == year);

        Map<String, List<Integer>> sortWeekMap = weekMap.entrySet().stream().sorted((e1, e2) ->
            Integer.compare(Integer.parseInt(e1.getKey()), Integer.parseInt(e2.getKey())))
            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1,
                LinkedHashMap::new));
        for (Entry<String, List<Integer>> map : sortWeekMap.entrySet()) {
            System.out.println(map.getKey() + "月:" + map.getValue().toString());
        }
    }
}

打印效果如下：