打印日历Java代码实现

问题：输入 年 - 月 打印出该月的日历

例如 2019-12

公式：

计算年月日是星期几 如 2019-11-1是星期几
公式：int week=(year-1+(year-1)/4-(year-1)/100+(year-1)/400+days)%7;

Java代码实现：

import java.util.Scanner;

public class Ecoh {
    /*
     *  给定年月如：2019，11，计算这个月有多少天
     *  闰年  这一年被四百整除or能被4整除但是不能被100整除
     */
    public  static int getMonthDay(int year,int month) {
        int days=0;
        switch(month) {
            case 4:
            case 6:
            case 9:
            case 11:
                days =30;
                break;
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
                days=31;
                break;
            case 2:
                if(year%400==0||(year%4==0 && year%100!=0)) {
                    days=29;
                }
                else {
                    days=28;
                }
                break;
            default:
                System.out.println("输入的不合法");
                break;
        }
        return days;
    }
    //给定年月，这天是这一年的第多少天
    public static int getYearDays(int year,int month,int day) {
        int days=0;
        for(int i=1;i<month;i++) {
            days+=getMonthDay(year,i);
        }
        days+=day;
        return days;
    }
    /*计算年月日是星期几    如 2019-11-1是星期几
     *公式：int week=(year-1+(year-1)/4-(year-1)/100+(year-1)/400+days)%7;
     */
    public static int getWeek(int year,int month,int day) {
        int days= getYearDays(year,month,day);           //调用getYearDays
        int week=(year-1+(year-1)/4-(year-1)/100+(year-1)/400+days)%7;    //days-----通过调用getYearDays获得
        return week;
    }
    //星期几就是几个空
    public  static void printCalendar(int year ,int month) {
        if(month<=3&&month>=1) System.out.println("Spring");
         else if(month<=6&&month>=3) System.out.println("Summer");
        else if(month<=9&&month>=6) System.out.println("Aumutn");
        else  System.out.println("Winter");
        System.out.println(" 日\t一\t二\t三\t四\t五\t六 ");
        System.out.println();
        int flag=0;
        int week= getWeek(year,month,1);        //求1号是星期几
        for(int i=0;i<week;i++) {
            flag++;
            System.out. print("\t");
        }
        int count=flag;
        int monthday=  getMonthDay(year,month);
        for(int j=1;j<=monthday;j++) {
            System.out.print(j+"\t");
            count++;
            if(count%7==0) {
              System.out.println("\n");
            }

        }
    }
    
    public static void main(String[] args) {
   /*TODO Auto-generated method stub 给定年月日，这天是这一年的第多少天
            int yeardays = getYearDays(2019,4,5);
            System.out.println(yeardays);

               // TODO Auto-generated method stub 给定年月，这个月有多少天
                  int monthdays = getMonthDay(2018,8);
                  System.out.println(monthdays);
                  // TODO Auto-generated method stub
                  int weeks = getWeek(2019,5,5);
                  System.out.println(weeks);

                    System.out.println("例如：2019按“回车”5");
                   Scanner in=new Scanner(System.in);
                   Scanner sc=new Scanner(System.in);
                  printCalendar(in.nextInt(),sc.nextInt());
      */
        Scanner s=new Scanner (System.in);
        while(true) {
            System.out.println("\n");
            String s1=s.nextLine();
            String []data=s1.split("-");       //split:对字符串进行分割
            printCalendar(new Integer(data[0]),new Integer(data[1]));
        }




    }

}

来源：CSDN

作者：划过一道痕

链接：https://blog.csdn.net/weixin_44115126/article/details/103600275