import java.text.ParseException;
import java.text.SimpleDateFormat;

public class DateValidator {
    public static boolean isValidDate(String dateStr, String format) {
        SimpleDateFormat sdf = new SimpleDateFormat(format);
        sdf.setLenient(false); // 关键设置，严格验证
        try {
            sdf.parse(dateStr);
            return true;
        } catch (ParseException e) {
            return false;
        }
    }
    
    // 使用示例
    public static void main(String[] args) {
        System.out.println(isValidDate("2023-02-29", "yyyy-MM-dd")); // false (2023不是闰年)
        System.out.println(isValidDate("2024-02-29", "yyyy-MM-dd")); // true (2024是闰年)
    }
}

public class LeapYearChecker {
    public static boolean isLeapYear(int year) {
        // 格里高利历闰年规则：
        // 1. 能被4整除但不能被100整除，或
        // 2. 能被400整除
        return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
    }
}

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

public class Java8DateValidator {
    public static boolean isValidDate(String dateStr, String pattern) {
        try {
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
            LocalDate.parse(dateStr, formatter);
            return true;
        } catch (DateTimeParseException e) {
            return false;
        }
    }
}

import java.time.LocalDate;

public class DateRangeValidator {
    public static boolean isWithinRange(LocalDate testDate, LocalDate startDate, LocalDate endDate) {
        return !(testDate.isBefore(startDate) || testDate.isAfter(endDate));
    }
}