您可以使用java标准类来实现这一点 LocalDate 以及 Period . 如果你需要从一个 String 到 LocalDate 首先你可以试试这个：

import java.time.LocalDate;
import java.time.Period;
import java.time.format.DateTimeFormatter;

public class CalendarAgeVerifier {

    public static void main(String[] args) {
        new CalendarAgeVerifier();
    }

    public CalendarAgeVerifier() {
        String date = "09/15/2000";//NOTE: the leading 0 in '09' is needed to parse the date correctly; otherwise you'll get a DateTimeParseException

        LocalDate currentDate = LocalDate.now();
        LocalDate enteredDate = parseDate(date);

        Period period = Period.between(enteredDate, currentDate);

        int age = period.getYears();

        System.out.println("Age: " + age);
    }

    public LocalDate parseDate(String date) {
        return LocalDate.parse(date, DateTimeFormatter.ofPattern("MM/dd/yyyy"));
    }
}