Java中实现带编号列表的用户选择与数据检索教程

// 假设 websites.getwebList() 返回一个存储网站URL的List<String>
List<String> websiteList = websites.getwebList();

// 遍历并显示带编号的网站列表
for (int i = 0; i < websiteList.size(); i++) {
    // 使用 (i + 1) 作为显示给用户的序号，确保每次从1开始
    System.out.println((i + 1) + " - " + websiteList.get(i));
}

// ... (列表生成代码) ...

// 提示用户输入选择
System.out.println("Enter the number of the website you want to access:");
int userNum = scnr.nextInt(); // 获取用户输入

// 将用户输入的1-based序号转换为0-based索引
int selectedIndex = userNum - 1;

// 获取网站列表的总大小，用于验证用户输入
int listSize = websiteList.size();

// 验证用户输入是否有效
if (selectedIndex >= 0 && selectedIndex < listSize) {
    // 如果输入有效，则根据索引获取并打印对应的数据
    System.out.println("Website: " + websiteList.get(selectedIndex));
    // 假设 usernames.getuserNameList() 和 passwords.getPassList() 也返回对应的List<String>
    System.out.println("Username: " + usernames.getuserNameList().get(selectedIndex));
    System.out.println("Password: " + passwords.getPassList().get(selectedIndex));
} else {
    // 如果输入无效，则提示用户重试
    System.out.println("Invalid selection. Please enter a number between 1 and " + listSize + ".");
}

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

// 模拟数据存储类
class WebsiteData {
    private List<String> webList = new ArrayList<>();
    private List<String> userNameList = new ArrayList<>();
    private List<String> passList = new ArrayList<>();

    public WebsiteData() {
        webList.add("website1.com");
        userNameList.add("user1");
        passList.add("pass1");

        webList.add("website2.com");
        userNameList.add("user2");
        passList.add("pass2");
    }

    public List<String> getwebList() { return webList; }
    public List<String> getuserNameList() { return userNameList; }
    public List<String> getPassList() { return passList; }
}

public class PasswordManagerDisplay {

    public static void main(String[] args) {
        Scanner scnr = new Scanner(System.in);
        WebsiteData websites = new WebsiteData(); // 假设这是存储数据的对象
        WebsiteData usernames = websites; // 简化，实际可能分开
        WebsiteData passwords = websites; // 简化，实际可能分开

        char yesNo = 'n'; // 模拟用户选择不添加密码，直接进入列表显示

        // PASSWORD Y/N LOOP (模拟外部循环)
        while (yesNo == 'n') {
            System.out.println("\n--- Available Websites ---");

            List<String> websiteList = websites.getwebList();
            int listSize = websiteList.size();

            // WEBSITE LIST MENU LOOP - 正确地显示带编号的列表
            for (int i = 0; i < listSize; i++) {
                System.out.println((i + 1) + " - " + websiteList.get(i));
            }

            // 提示用户输入选择
            System.out.println("Enter the number of the website you want to access (or 0 to exit):");
            int userNum = scnr.nextInt();

            // 如果用户输入0，则退出循环
            if (userNum == 0) {
                System.out.println("Exiting website selection.");
                break; // 跳出while循环
            }

            // 将用户输入的1-based序号转换为0-based索引
            int selectedIndex = userNum - 1;

            // 验证用户输入是否在有效范围内
            if (selectedIndex >= 0 && selectedIndex < listSize) {
                // PRINT WEBSITE LIST - 成功访问并打印数据
                System.out.println("\n--- Details for your selection ---");
                System.out.println("Website: " + websiteList.get(selectedIndex));
                System.out.println("Username: " + usernames.getuserNameList().get(selectedIndex));
                System.out.println("Password: " + passwords.getPassList().get(selectedIndex));

                // 成功访问后，可以根据需求选择是否退出或继续
                // 例如，这里选择退出，如果想继续选择，可以移除break
                yesNo = 'y'; // 模拟完成操作，退出外部循环
            } else {
                System.out.println("Invalid selection. Please enter a number between 1 and " + listSize + ".");
            }
            // 如果用户输入无效，yesNo仍为'n'，循环会继续，再次显示列表
        }
        scnr.close();
    }
}