Java 短消息管理系统：实现接收、显示、阅读、删除和清空功能

package Example; import java.util.ArrayList; import java.util.Date; import java.util.Scanner; class Message { private String content; private Date timestamp;

public Message(String content, Date timestamp) {
    this.content = content;
    this.timestamp = timestamp;
}

public String getContent() {
    return content;
}

public Date getTimestamp() {
    return timestamp;
}

}

public class Example2 { private static ArrayList messages = new ArrayList<>();

public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    while (true) {
        System.out.println("请选择操作：");
        System.out.println("1. 短消息接收");
        System.out.println("2. 短列表显示所有短消息");
        System.out.println("3. 阅读短消息");
        System.out.println("4. 删除短消息");
        System.out.println("5. 清空所有短消息");
        System.out.println("0. 退出程序");

        int choice = scanner.nextInt();
        scanner.nextLine(); // 读取换行符

        switch (choice) {
            case 1:
                receiveMessage(scanner);
                break;
            case 2:
                displayMessages();
                break;
            case 3:
                readMessage(scanner);
                break;
            case 4:
                deleteMessage(scanner);
                break;
            case 5:
                clearMessages();
                break;
            case 0:
                System.exit(0);
                break;
            default:
                System.out.println("无效的操作，请重新选择。");
        }
    }
}

private static void receiveMessage(Scanner scanner) {
    System.out.println("请输入短消息内容：");
    String content = scanner.nextLine();

    Message message = new Message(content, new Date());
    if (messages.size() >= 20) {
        messages.remove(0);
    }
    messages.add(message);

    System.out.println("短消息接收成功！");
}

private static void displayMessages() {
    if (messages.size() == 0) {
        System.out.println("暂无短消息。");
    } else {
        System.out.println("短消息列表：");
        for (int i = 0; i < messages.size(); i++) {
            Message message = messages.get(i);
            System.out.println(i + 1 + ". " + message.getContent());
        }
    }
}

private static void readMessage(Scanner scanner) {
    System.out.println("请输入要阅读的短消息编号：");
    int index = scanner.nextInt();
    scanner.nextLine(); // 读取换行符

    if (index < 1 || index > messages.size()) {
        System.out.println("无效的短消息编号。");
    } else {
        Message message = messages.get(index - 1);
        System.out.println("短消息内容：" + message.getContent());
        System.out.println("短消息时间：" + message.getTimestamp());
    }
}

private static void deleteMessage(Scanner scanner) {
    System.out.println("请输入要删除的短消息编号：");
    int index = scanner.nextInt();
    scanner.nextLine(); // 读取换行符

    if (index < 1 || index > messages.size()) {
        System.out.println("无效的短消息编号。");
    } else {
        messages.remove(index - 1);
        System.out.println("短消息删除成功！");
    }
}

private static void clearMessages() {
    messages.clear();
    System.out.println("所有短消息已清空！");
}

}