本关任务：编写程序，实现以下功能： 输入一个日期（年月日），计算该日期是星期几。并输出日期和星期几。 例如： 输入：2022 3 24 输出：今天是2022 MARCH 24 THURSDAY

以下是一个实现题目要求的Java程序：

import java.util.*;

public class WeekdayCalculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // 获取输入的年月日
        System.out.print("请输入年份: ");
        int year = scanner.nextInt();
        System.out.print("请输入月份: ");
        int month = scanner.nextInt();
        System.out.print("请输入日期: ");
        int day = scanner.nextInt();

        // 使用Calendar类计算星期几
        Calendar calendar = Calendar.getInstance();
        calendar.set(year, month - 1, day);
        int weekday = calendar.get(Calendar.DAY_OF_WEEK);

        // 将星期几转换为字符串
        String[] weekdays = {"SUNDAY", "MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY", "SATURDAY"};
        String weekdayStr = weekdays[weekday - 1];

        // 将月份转换为字符串
        String[] months = {"JANUARY", "FEBRUARY", "MARCH", "APRIL", "MAY", "JUNE", "JULY", "AUGUST", "SEPTEMBER", "OCTOBER", "NOVEMBER", "DECEMBER"};
        String monthStr = months[month - 1];

        // 输出结果
        System.out.println("今天是" + year + " " + monthStr + " " + day + " " + weekdayStr);
    }
}

该程序首先使用Scanner类获取用户输入的年月日，然后使用Calendar类计算该日期是星期几。最后，将年月日和星期几输出为字符串。运行程序，输入年月日后即可得到输出结果。