Java任意输入年月日并判断这天是星期几

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

import java.util.Scanner;

public class Datetest{public static void main(String[] args){System.out.println("请输入三个以内的数字，并以#结束：");Scanner input = new Scanner(System.in);String str="";StringBuffer sb = new StringBuffer();Calendar calendar = Calendar.getInstance();String weekd = "日一二三四五六";while(!(str=input.next()).equals("#")){sb.append(str+";");}String subs=sb.toString();String[] arr = subs.split(";");if(arr.length!=3){System.out.println("输入数据错误！");}else{String date = arr[0]+"-"+arr[1]+"-"+arr[2];SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");Date datet = null;try {datet = f.parse(date);} catch (ParseException e) {// TODO Auto-generated catch blocke.printStackTrace();}calendar.setTime(datet);int day = calendar.get(Calendar.DAY_OF_WEEK);System.out.println("这天是星期"+weekd.substring(day-1,day));}}}