用java写一个简单地用户从键盘输入身份证号请从身份证号码中提取出生年月日并以yyyy-mm-dd的格式输出。

import java.util.Scanner;

public class IdCardExtract {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入身份证号码：");
        String idCard = scanner.nextLine();
        String birthday = idCard.substring(6, 14);
        String year = birthday.substring(0, 4);
        String month = birthday.substring(4, 6);
        String day = birthday.substring(6);
        System.out.println("出生年月日为：" + year + "-" + month + "-" + day);
    }

}
``