打印给定年月的日历

import java.util.Scanner;
public class PrintCalendar {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("输入年份：");
int year = input.nextInt();
System.out.print("输入月份(1月--12月)：");
int month = input.nextInt();
printMonth(year, month);

}

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\t\t" + getMonthName(month) + " " + year);
System.out.println("----------------------------------");
System.out.println("      Sun Mon Tue Wed thu Fri Sat ");
}

public static void printMonthBody(int year, int month) {
int starDay = getStartDay(year, month);
int numberOfDaysInMonth = getNumberOfDayInMonth(year, month);
int i = 0;
int weeks = getNumberWeekDay(year, month);
System.out.printf("%4d", weeks);
for (i = 0; i < starDay; i++)
System.out.print("\t");
for (i = 1; i <= numberOfDaysInMonth; i++) {
System.out.printf("%4d", i);
if ((i + starDay) % 7 == 0) {
System.out.println();
weeks = weeks + 1;
System.out.printf("%4d", weeks);
}
}
System.out.println();
}

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;
}

/**
* 获取每月一号是星期几
*/
public static int getStartDay(int year, int month) {
final int STAR_DAY_FOR_JAN_1_1800 = 3;
int totalNumberOfDays = getTotalNumberOfDays(year, month);
return (totalNumberOfDays + STAR_DAY_FOR_JAN_1_1800) % 7;
}

public static int getTotalNumberOfDays(int year, int month) {
int total = 0;
for (int i = 1800; i < year; i++) {
if (isLeapYear(i)) {
total = total + 366;
} else {
total = total + 365;
}
}
for (int i = 1; i < month; i++)
total = total + getNumberOfDayInMonth(year, i);

return total;
}

/**
* @param year
* @param month
* @return weeks 返回截止当月之前的有多少周
*/
public static int getNumberWeekDay(int year, int month) {
int totalDays = 0;
int startDays = getStartDay(year, month);
int weeks;
for (int i = 1; i < month; i++)
totalDays = totalDays + getNumberOfDayInMonth(year, i);
if (startDays <= 4) {
weeks = ((totalDays - (7 - startDays)) / 7 + 1);
} else {
weeks = ((totalDays - (7 - startDays)) / 7);
}
if (startDays != 0 && month != 1) {
weeks++;
}
return weeks;

/**
 * Created by zhouyubin on 7/15/14.
 */
}

public static int getNumberOfDayInMonth(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;
}

public static boolean isLeapYear(int year) {
if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {
return true;
}
return false;
}

}

运行效果：

输入年份：2014
输入月份(1月--12月)：7
            July 2014
----------------------------------
      Sun Mon Tue Wed thu Fri Sat
  27           1   2   3   4   5
  28   6   7   8   9  10  11  12
  29  13  14  15  16  17  18  19
  30  20  21  22  23  24  25  26
  31  27  28  29  30  31

Process finished with exit code 0