Java图书借阅逾期提醒练习

import java.util.Date;
import java.text.SimpleDateFormat;
public class BookReturnReminder {
public static void main(String[] args) {
// 模拟借书日期（例如：两周前）
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
long borrowTime = System.currentTimeMillis() - (14  24  60  60  1000L); // 14天前
Date returnDeadline = new Date(borrowTime + 14  24  60  60  1000L); // 到期日
    Date today = new Date();
    long diffInMillis = today.getTime() - returnDeadline.getTime();
    int overdueDays = (int)(diffInMillis / (24 * 60 * 60 * 1000));

    if (overdueDays < 0) {
        System.out.println("图书未逾期，按时归还！");
    } else if (overdueDays >= 1 && overdueDays <= 7) {
        System.out.println("已逾期，请尽快归还！");
    } else if (overdueDays > 7) {
        System.out.println("严重逾期，需缴纳罚款！");
    } else {
        System.out.println("今日到期，建议立即归还。");
    }
}
}

import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
public class BookReturnReminderModern {
public static void main(String[] args) {
LocalDate borrowDate = LocalDate.of(2025, 3, 1);
LocalDate dueDate = borrowDate.plusDays(14); // 14天后到期
LocalDate today = LocalDate.now();
    long overdueDays = ChronoUnit.DAYS.between(dueDate, today);

    if (overdueDays < 0) {
        System.out.println("图书未逾期，按时归还！");
    } else if (overdueDays <= 7) {
        System.out.println("已逾期，请尽快归还！");
    } else {
        System.out.println("严重逾期，需缴纳罚款！");
    }
}
}