Java实现打印日历的功能

　　编写一个程序，显示给定年月的日历。程序提示用户输入年份和月份，然后显示该月的整个日历。

　　代码：

 import java.util.Scanner;
 public class PrintCalendar{
     public static void main(String[] args){
         Scanner input=new Scanner(System.in);

             System.out.print("Enter full year(e.g.,2011): ");
             int Year=input.nextInt();

             System.out.print("Enter month as a number between 1 and 12: ");
             int Month=input.nextInt();

     //    int year=inputYear();
         //int month=inputMonth();
         printMonth(Year, Month);
     }
 /*
     public static int inputYear(){
         boolean flag=true;
         Scanner input=new Scanner(System.in);
         while(flag){
             System.out.print("Enter full year(e.g.,2011): ");
             int iYear=input.nextInt();
             if(iYear>=1800){
                 flag = false;
             }
         }
         return iYear;
     }

     public static int inputMonth(){
         boolean flag=true;
         Scanner input=new Scanner(System.in);
         while(flag){
             System.out.print("Enter month as a number between 1 and 12: ");
             int iMonth=input.nextInt();
             if(iMonth>=1 && iMonth<=12){
                 flag = false;
             }
         }
         return iMonth;
     }*/

     public static void printMonth(int year, int month){
         printMonthTitle(year, month);
         printMonthBody(year,month);
     }

     public static void printMonthTitle(int year, int month){
         System.out.println("\t" + getMonthName(month)+"\t" +year);
         System.out.println("-----------------------------------");
         System.out.println("Mon Tue Wed Thu Fri Sat Sun");
     }
     public static String getMonthName(int month){
         String monthName="";
         switch (month){
             case 1: monthName="January"; break;
             case 2: monthName="February"; break;
             case 3: monthName="March"; break;
             case 4: monthName="April"; break;
             case 5: monthName="May"; break;
             case 6: monthName="June"; break;
             case 7: monthName="July"; break;
             case 8: monthName="August"; break;
             case 9: monthName="September"; break;
             case 10: monthName="October"; break;
             case 11: monthName="November"; break;
             case 12: monthName="December"; break;
         }

         return monthName;
     }

     public static void printMonthBody(int year, int month){

         //Get start day of the week for the first date int the month
         int startDay=getStartDay(year,month);

         //Get number of days in the month
         int numberOfDaysInMonth = getNumberOfDaysInMonth(year,month);

         //Pad space before the first day of the month
         int i=0;
         for(i=1; i< startDay; i++){
             System.out.print("    ");
         }
         for(i=1; i<=numberOfDaysInMonth;i++){
             System.out.printf("%-4d", i);

             if((i+startDay-1)%7==0)
                 System.out.println();
         }
         System.out.println();
     }

     /** Get the start day of month/1/year */
     public static int getStartDay(int year, int month){
         final int START_DAY_FOR_JAN_1_1800 = 3;

         //Get the total number of days from 1/1/1800 to month/1/year
         int totalNumberOfDays= getTotalNumberOfDays(year,month);

         //Return the start day for month/1/year
         return (totalNumberOfDays+START_DAY_FOR_JAN_1_1800)%7;
     }

     /** Get the total number of days from January 1, 1800; */
     public static int getTotalNumberOfDays(int year, int month){
         int total = 0;

         //get total number of days from 1800 to 1/1/year
         for(int i = 1800; i<year; i++){
             if(isLeapYear(i))
                 total = total + 366;
             else
                 total = total + 365;
         }

         //add days from January to the month prior to the calendar month
         for(int i = 0; i<month;i++)
             total +=getNumberOfDaysInMonth(year, i);

         return total;
     }

     /** Get the number of days in a month */
     public static int getNumberOfDaysInMonth(int year, int month){
         if(month==1||month==3||month==5||month==7||month==8||month==10||month==12)
             return 31;
         if(month==4||month==6||month==9||month==11)
             return 30;
         if(month==2)
             return isLeapYear(year)?29:28;
         return 0;
     }

     /** Determine if it is a leap year */
     public static boolean isLeapYear(int year){
         return year % 400 == 0  ||  (year % 4 == 0  &&  year % 100 != 0);
     }
 }

执行效果：