输入年份跟月份输出该月有多少天用jave代码写出来

以下是Java代码：

import java.util.Scanner;

public class Main {

    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();

        int days;

        switch (month) {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12:
                days = 31;
                break;
            case 4:
            case 6:
            case 9:
            case 11:
                days = 30;
                break;
            case 2:
                if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
                    days = 29;
                } else {
                    days = 28;
                }
                break;
            default:
                days = -1;
                break;
        }

        if (days != -1) {
            System.out.printf("%d年%d月有%d天\n", year, month, days);
        } else {
            System.out.println("输入的月份不正确！");
        }

    }

}