编写程序: 从键盘分别输入年、月、日，判断这一天是当年的第几天

编写程序: 从键盘分别输入年、月、日，判断这一天是当年的第几天
    注:判断一年是否是闰年的标准
    1)可以被4整除，但不可被100整除或
    2)可以被400整除

import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int februaryDay = 28;
        while (true){
            System.out.println("请输入year：");
            int year = sc.nextInt();
            System.out.println("请输入month：");
            int month = sc.nextInt();
            System.out.println("请输入day：");
            int day = sc.nextInt();

            if (year <= 0){
                System.out.println("您输入的年份有误！");
            }else if ((year % 4 ==0 && year % 100 != 0) || year % 400 ==0){
                //闰年
                if (month == 1 || month == 3 || month == 5 || month== 7 || month == 8 || month == 10 || month == 12){
                    if (day > 0 && day <= 31){
                        date(year,month,day);
                        break;
                    }else {
                        System.out.println("您输入的日期有误！");
                    }
                }else if (month == 2){
                    if (day > 0 && day <= 29){
                        date(year,month,day);
                        break;
                    }else {
                        System.out.println("您输入的日期有误！");
                    }
                }else if (month == 4 || month == 6 || month == 9 || month== 11){
                    if (day > 0 && day <= 28){
                        date(year,month,day);
                        break;
                    }else {
                        System.out.println("您输入的日期有误！");
                    }
                }else {
                    System.out.println("您输入的月份有误！");
                }
            }else {
                //非闰年
                if (month == 1 || month == 3 || month == 5 || month== 7 || month == 8 || month == 10 || month == 12){
                    if (day > 0 && day <= 31){
                        date(year,month,day);
                        break;
                    }else {
                        System.out.println("您输入的日期有误！");
                    }
                }else if (month == 2){
                    if (day > 0 && day <= februaryDay){
                        date(year,month,day);
                        break;
                    }else {
                        System.out.println("您输入的日期有误！");
                    }
                }else if (month == 4 || month == 6 || month == 9 || month== 11){
                    if (day > 0 && day <= 28){
                        date(year,month,day);
                        break;
                    }else {
                        System.out.println("您输入的日期有误！");
                    }
                }else {
                    System.out.println("您输入的月份有误！");
                }

            }

        }

    }

    public static void date(int year,int month,int day){
        int sumDays = 0;
        switch (month){
            case 12:
                sumDays += 30;
            case 11:
                sumDays += 31;
            case 10:
                sumDays += 30;
            case 9:
                sumDays += 31;
            case 8:
                sumDays += 31;
            case 7:
                sumDays += 30;
            case 6:
                sumDays += 31;
            case 5:
                sumDays += 30;
            case 4:
                sumDays += 31;
            case 3:
                if ((year % 4 ==0 && year % 100 != 0) || year % 400 ==0){
                    sumDays += 29;
                }else {
                    sumDays += 28;
                }
            case 2:
                sumDays += 31;
            case 1:
                sumDays += day;
                break;
        }
        System.out.println(year+"年"+month+"月"+day+"日是"+year+"年的第"+sumDays+"天");
    }
}