public static void main(String[] args) {
String s = “2021110506:45:00”;
String year=s.substring(0,4);
String moon=s.substring(4,6);
String day=s.substring(6,8);
String time=s.substring(8,16);
System.out.println(year);
System.out.println(moon);
System.out.println(day);
System.out.println(time);
String date = year+"-"+moon+"-"+day+" " + time;
System.out.println(date);
}