java菜单如何循环

Java 菜单循环实现方法

使用 while 循环实现基础菜单循环

import java.util.Scanner;

public class MenuLoop {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        boolean running = true;

        while (running) {
            System.out.println("1. 选项一");
            System.out.println("2. 选项二");
            System.out.println("3. 退出");
            System.out.print("请输入选择: ");

            int choice = scanner.nextInt();

            switch (choice) {
                case 1:
                    System.out.println("执行选项一");
                    break;
                case 2:
                    System.out.println("执行选项二");
                    break;
                case 3:
                    running = false;
                    break;
                default:
                    System.out.println("无效输入");
            }
        }
        scanner.close();
    }
}

使用 do-while 循环确保至少执行一次

import java.util.Scanner;

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

        do {
            System.out.println("1. 添加记录");
            System.out.println("2. 删除记录");
            System.out.println("3. 退出系统");
            System.out.print("请选择: ");

            choice = scanner.nextInt();

            if (choice == 1) {
                System.out.println("添加记录功能");
            } else if (choice == 2) {
                System.out.println("删除记录功能");
            } else if (choice != 3) {
                System.out.println("无效选项");
            }
        } while (choice != 3);

        scanner.close();
    }
}

带输入验证的增强版菜单循环

import java.util.Scanner;

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

        while (true) {
            System.out.println("\n--- 主菜单 ---");
            System.out.println("1. 查看数据");
            System.out.println("2. 修改数据");
            System.out.println("3. 退出");
            System.out.print("请选择(1-3): ");

            try {
                choice = Integer.parseInt(scanner.nextLine());

                switch (choice) {
                    case 1:
                        System.out.println("显示数据...");
                        break;
                    case 2:
                        System.out.println("修改数据...");
                        break;
                    case 3:
                        System.out.println("退出系统");
                        return;
                    default:
                        System.out.println("请输入1-3的数字");
                }
            } catch (NumberFormatException e) {
                System.out.println("请输入有效数字");
            }
        }
    }
}

基于枚举的高级菜单实现

import java.util.Scanner;

public class EnumMenu {
    enum MenuOption { LIST, ADD, DELETE, EXIT }

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

        while (true) {
            System.out.println("\nL - 列表");
            System.out.println("A - 添加");
            System.out.println("D - 删除");
            System.out.println("X - 退出");
            System.out.print("选择: ");

            String input = scanner.nextLine().toUpperCase();

            try {
                option = MenuOption.valueOf(input);

                switch (option) {
                    case LIST:
                        System.out.println("显示列表");
                        break;
                    case ADD:
                        System.out.println("添加项目");
                        break;
                    case DELETE:
                        System.out.println("删除项目");
                        break;
                    case EXIT:
                        System.out.println("再见!");
                        return;
                }
            } catch (IllegalArgumentException e) {
                System.out.println("无效选项");
            }
        }
    }
}

这些示例展示了不同复杂度的Java菜单循环实现方法，从基础版本到带输入验证和枚举的高级版本。可以根据具体需求选择适合的实现方式。