如何从这个字符串字段中获取天数？

var dateString = "2022-01-01";
var dateParts = dateString.split("-");
var date = new Date(dateParts[0], parseInt(dateParts[1]) - 1, dateParts[2]);
var today = new Date();
var timeDiff = today.getTime() - date.getTime();
var daysDiff = Math.floor(timeDiff / (1000 * 3600 * 24));
console.log(daysDiff);

from datetime import datetime

date_string = "01/01/2022"
date = datetime.strptime(date_string, "%d/%m/%Y")
today = datetime.now()
days_diff = (today - date).days
print(days_diff)

String dateString = "20220101";
int year = Integer.parseInt(dateString.substring(0, 4));
int month = Integer.parseInt(dateString.substring(4, 6));
int day = Integer.parseInt(dateString.substring(6, 8));
int todayYear = java.time.Year.now().getValue();
int todayMonth = java.time.Month.now().getValue();
int todayDay = java.time.LocalDate.now().getDayOfMonth();
int daysDiff = (todayYear - year) * 365 + (todayMonth - month) * 30 + (todayDay - day);
System.out.println(daysDiff);