构造日期类MyDate类，包含年月日

创建一个名为`MyDate`的构造日期类，通常会包含私有变量分别代表年、月、日，以及相应的公共构造函数、getter和setter方法。以下是这个类的一个简单实现示例：

public class MyDate {
    private int year;
    private int month;
    private int day;

    // 默认构造函数，设置年月日为当前时间
    public MyDate() {
        this(Calendar.getInstance().get(Calendar.YEAR),
             Calendar.getInstance().get(Calendar.MONTH) + 1,
             Calendar.getInstance().get(Calendar.DAY_OF_MONTH));
    }

    // 具体的构造函数接受年月日作为参数
    public MyDate(int year, int month, int day) {
        if (month < 1 || month > 12 || day < 1) {
            throw new IllegalArgumentException("Invalid date");
        }
        this.year = year;
        this.month = month;
        this.day = day;
    }

    // Getter methods
    public int getYear() {
        return year;
    }
    
    public int getMonth() {
        return month;
    }

    public int getDay() {
        return day;
    }

    // Setter methods
    public void setYear(int year) {
        this.year = year;
    }

    public void setMonth(int month) {
        this.month = month;
    }

    public void setDay(int day) {
        this.day = day;
    }

    // Overriding toString() method for better readability
    @Override
    public String toString() {
        return String.format("%d-%02d-%02d", year, month, day);
    }
}