如何通过使用from方法传递参数来为属性分配值？

Question

我只需要使用一种设置方法就可以将YEAR，MONTH，DAY属性分配给值。因此，我通过逐行调用set方法，将DATE.YEAR，DATE.MONTH，DATE.DATE作为参数传递给参数。您可以对set方法进行任何更改。但是您不能更改主要方法。

   class Date{
    static int YEAR;
    static int MONTH;
    static int DAY;

    public void set(int field,int value){
        //i need to put code here to assign YEAR, MONTH, DAY to values
    }
    public void printDate(){
        System.out.println(YEAR+"-"+MONTH+"-"+DAY);
    }

}
class Demo{
    public static void main(String args[]){
        Date d1=new Date();
        d1.set(Date.YEAR,2016); //set(int field, int value)
        d1.set(Date.MONTH,05);
        d1.set(Date.DAY,30);
        d1.printDate(); //2016-5-30
    }
}

Answer 1

    class Date {

        static final int YEAR = 0;
        static final int MONTH = 1;
        static final int DAY = 2;

        private int year;
        private int month;
        private int day;

        public void set(int field, int value) {
            if (field == YEAR)
                this.year = value;
            else if (field == MONTH)
                this.month = value;
            else if (field == DAY)
                this.day = value;
        }

        public void printDate() {
            System.out.println(year + "-" + month + "-" + day);
        }
    }