Java实现简易日程提醒工具方法

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
class Reminder {
String title;
LocalDateTime time;
public Reminder(String title, LocalDateTime time) {
    this.title = title;
    this.time = time;
}

@Override
public String toString() {
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm");
    return time.format(formatter) + " - " + title;
}
}
public class SimpleReminderTool {
private static List reminders = new ArrayList<>();
private static Scanner scanner = new Scanner(System.in);
private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm");
public static void main(String[] args) {
    System.out.println("启动小型日程提醒工具...");

    // 启动后台线程定期检查提醒
    ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
    scheduler.scheduleAtFixedRate(SimpleReminderTool::checkReminders, 0, 30, TimeUnit.SECONDS);

    // 主交互循环
    while (true) {
        showMenu();
        String choice = scanner.nextLine().trim();

        switch (choice) {
            case "1":
                addReminder();
                break;
            case "2":
                listReminders();
                break;
            case "3":
                System.out.println("退出程序。");
                scheduler.shutdown();
                scanner.close();
                return;
            default:
                System.out.println("无效选择，请重新输入。");
        }
    }
}

private static void showMenu() {
    System.out.println("\n--- 日程提醒工具 ---");
    System.out.println("1. 添加提醒");
    System.out.println("2. 查看所有提醒");
    System.out.println("3. 退出");
    System.out.print("请选择操作: ");
}

private static void addReminder() {
    try {
        System.out.print("请输入提醒标题: ");
        String title = scanner.nextLine();

        System.out.print("请输入提醒时间 (格式: yyyy-MM-dd HH:mm): ");
        String timeStr = scanner.nextLine();
        LocalDateTime time = LocalDateTime.parse(timeStr, formatter);

        reminders.add(new Reminder(title, time));
        System.out.println("✅ 提醒已添加: " + title + " at " + timeStr);
    } catch (Exception e) {
        System.out.println("❌ 时间格式错误，请使用 yyyy-MM-dd HH:mm 格式。");
    }
}

private static void listReminders() {
    if (reminders.isEmpty()) {
        System.out.println("暂无提醒。");
    } else {
        System.out.println("\n当前所有提醒:");
        reminders.stream()
            .sorted((a, b) -> a.time.compareTo(b.time))
            .forEach(System.out::println);
    }
}

private static void checkReminders() {
    LocalDateTime now = LocalDateTime.now();
    reminders.removeIf(reminder -> {
        if (now.isAfter(reminder.time) || now.isEqual(reminder.time)) {
            System.out.println("\n? 提醒触发! " + reminder.title + " 到时间了！");
            return true; // 移除已触发的提醒
        }
        return false;
    });
}
}