以下是一个简单的Java万年历实现代码：
import java.util.Scanner;public class CalendarProgram { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.print("请输入年份："); int year = scanner.nextInt(); System.out.print("请输入月份："); int month = scanner.nextInt(); printCalendar(year, month); scanner.close(); } public static void printCalendar(int year, int month) { int daysInMonth = getDaysInMonth(year, month); int startDayOfWeek = getStartDayOfWeek(year, month); System.out.println("日\t一\t二\t三\t四\t五\t六"); for (int i = 0; i < startDayOfWeek; i++) { System.out.print("\t"); } for (int day = 1; day <= daysInMonth; day++) { System.out.print(day + "\t"); if ((day + startDayOfWeek) % 7 == 0) { System.out.println(); } } } public static int getDaysInMonth(int year, int month) { int[] daysInMonth = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; if (month == 2 && isLeapYear(year)) { return 29; } return daysInMonth[month - 1]; } public static int getStartDayOfWeek(int year, int month) { int totalDays = 0; for (int y = 1900; y < year; y++) { totalDays += isLeapYear(y) ? 366 : 365; } for (int m = 1; m < month; m++) { totalDays += getDaysInMonth(year, m); } return (totalDays + 1) % 7; } public static boolean isLeapYear(int year) { return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0); }}这个代码实现了一个简单的万年历程序。用户可以输入年份和月份，然后程序会打印出对应的日历。程序使用了getDaysInMonth()函数来计算每个月的天数，getStartDayOfWeek()函数来计算每个月的第一天是星期几，isLeapYear()函数来判断是否是闰年。最后，printCalendar()函数根据上述计算结果打印出日历。
