JAVA 打印指定月份日历

  1 package learnExercise;
  2 
  3 import java.util.Scanner;
  4 
  5 public class PrintCalender {
  6 
  7     /**
  8      * @param args
  9      */
 10     public static void main(String[] args) {
 11         // TODO Auto-generated method stub
 12         Scanner input=new Scanner(System.in);
 13         
 14         System.out.print("Enter full year (e.g.,2001): ");
 15         int year=input.nextInt();
 16         
 17         System.out.print("Enter month as number between 1 and 12: ");
 18         int month=input.nextInt();
 19         
 20         printMonth(year,month);
 21 
 22     }
 23 
 24     private static void printMonth(int year, int month) {
 25         // TODO Auto-generated method stub
 26         printMonthTitle(year, month);
 27         printMonthBody(year, month);
 28     }
 29     
 30     public static void printMonthTitle(int year, int month){
 31         System.out.println("        "+getMonthName(month)+" "+year);
 32         System.out.println("-------------------------");
 33         System.out.println(" Sun Mont Tue Wed Thu Fri Sat");
 34         
 35     }
 36     
 37     //打印月份主体
 38     public static void printMonthBody(int year,int month){
 39         int startDay=getStartDay(year, month);
 40         int numberOfDaysInMonth=getNumberOfDaysInMonth(year, month);
 41         for(int i=0;i<startDay;i++)
 42             System.out.print("    ");
 43         for(int i=1;i<=numberOfDaysInMonth;i++){
 44             System.out.printf("%4d",i);
 45             if((i+startDay)%7==0)
 46                 System.out.println();
 47         }
 48         System.out.println();
 49     }
 50     
 51     public static String getMonthName(int month){
 52         String  monthName="";
 53         switch(month){
 54         case 1: monthName="January";break;
 55         case 2: monthName="February";break;
 56         case 3: monthName="March";break;
 57         case 4: monthName="April";break;
 58         case 5: monthName="May";break;
 59         case 6: monthName="June";break;
 60         case 7: monthName="July";break;
 61         case 8: monthName="August";break;
 62         case 9: monthName="September";break;
 63         case 10: monthName="October";break;
 64         case 11: monthName="Nobember";break;
 65         case 12: monthName="December";break;
 66         }
 67         return monthName;
 68     }
 69     //获取指定月份的第一天是周几
 70     public static  int getStartDay(int year, int month){
 71         final int START_DAY_FOR_JAN_1_1800=8;
 72         int totalNumberOfDays=getTotalNumberOfDays(year,month);
 73         
 74         return (totalNumberOfDays+START_DAY_FOR_JAN_1_1800)%7;
 75     }
 76     //返回总共的天数，从1800年1月1日开始计算,直到指定月份1日的前一天
 77     public static int getTotalNumberOfDays(int year,int month){
 78         int total=0;
 79         for(int i=1800;i<year;i++)
 80             if(isLeapYear(i))
 81                 total=total+366;
 82             else 
 83                 total=total+365;
 84         
 85         for(int i=1;i<month;i++)
 86             total=total+getNumberOfDaysInMonth(year,i);
 87         
 88         return total;
 89     }
 90     
 91     //返回指定月份的天数
 92     public static int getNumberOfDaysInMonth(int year,int month){
 93         int result=0;
 94         switch (month){
 95         case 1:
 96         case 3:
 97         case 5:
 98         case 7:
 99         case 8:
100         case 10:
101         case 12:
102             result=31;
103             break;
104         case 4:
105         case 6:
106         case 9:
107         case 11:
108             result=30;
109             break;
110         case 2:
111             result=isLeapYear(year)?29:28;
112             break;
113         }
114         return result;
115     }
116     
117     //判断是否为闰年
118     public static boolean isLeapYear(int year){
119         return (year%400==0)||(year%4==0&&year%100!=0);
120     }
121 
122 }
方法抽象将程序模块化为整齐、层次分明的形式。将程序由简洁的方法构成的集合，比其他方式更容易编写、调试、维护和修改。
编写大型程序时，可以使用自顶向下或自底向上的方法，不要一次性地编写整个程序。
如果您觉得感兴趣的话，可以添加我的微信公众号：一步一步学Python