利用calendar工具类计算今年的第几天

import java.text.ParseException;
import java.text.SimpleDateFormat;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int year = sc.nextInt();
        int month = sc.nextInt();
        int day = sc.nextInt();
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd"); 
        Calendar cal=Calendar.getInstance(); 
        String monthstr = month > 9 ? month+"" : "0"+ month;
        String str = year + "-"+ monthstr +"-" + day;
        try{
            cal.setTime(df.parse(str)); 
        } catch (Exception e){
            e.printStackTrace();
        }
        System.out.print(cal.get(6));
    }
}