Java实现计算写博客多久了？

import java.util.Date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Scanner;
public class DataTest {

	public static void main(String[] args) throws ParseException {
		
		System.out.print("输入开始写博客的时间(yyyy-MM-dd):");
		String str = new Scanner(System.in).nextLine();
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		Date date = sdf.parse(str);
		
		long time = System.currentTimeMillis() - date.getTime();
		time = time / 1000 / 24 / 60 / 60;
		System.out.println("Mo*◑，你好！你已经开始写博客 " + time + "天了！");
	
	}

}