Enter the date format string as the production date of the commodity, and enter the shelf life (days); Calculate the number of days until today before the expiration date of the product. 1. Change the

package demo;

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

/**
 * @author : htf 
 	                   Enter the date format string as the production date of the product , Enter the shelf life （ God ）; Calculation section   Until today , How many days will the product expire 
         1、 The console input string is converted to date format 
        2、 Add the input date to the shelf life days  
        3、 Get the current system date , Compare two dates , If the output is expired “ This item has expired ”
 */
public class Test1 {
	
	public static void main(String[] args) throws ParseException {

		System.out.println(" Please enter the production date （yyyy-MM-dd）");
		Scanner sc=new Scanner(System.in);
		String d=sc.next();// Keyboard access time 2022-01-10
		System.out.println(" Please enter the shelf life ( God )");
		int day=sc.nextInt();// Acquisition time 
		
		SimpleDateFormat sDateFormat=new SimpleDateFormat("yyyy-MM-dd");// Transformation format 
		Date date =sDateFormat.parse(d);// The time character obtained by the keyboard is converted into time 
		Calendar c =Calendar.getInstance();
		c.setTime(date);// Setup time 
		c.add(Calendar.DATE, day);// Set the shelf life time 
		String str = sDateFormat.format(c.getTime());// Conversion time 
		
		System.out.println(" Today's date is ："+sDateFormat.format(new Date()));// current time 
		// Compare the number of milliseconds of the current date with the number of milliseconds after the number of days you want to add , If it is less than the number of days you want to add , The product has expired 
		if(c.getTimeInMillis()<new Date().getTime()) {
			System.out.println(" It's overdue ");
		}else {
			 // You want to add the millisecond value of the following days minus the millisecond value of the current time 
			 long g=c.getTimeInMillis()-new Date().getTime();
			 long t=g/(3600*24*1000);// Format days 
			System.out.println(" There are also commodities "+t+" Days overdue ");
		}
	}

}