基于 C# Trie 树的'管控员工上网 URL 过滤与匹配优化方案探索

using System;
using System.Collections.Generic;
public class TrieNode
{
    public char Character { get; set; }
    public Dictionary<char, TrieNode> Children { get; set; }
    public bool IsEndOfUrl { get; set; }
    public TrieNode(char character)
    {
        Character = character;
        Children = new Dictionary<char, TrieNode>();
        IsEndOfUrl = false;
    }
}
public class UrlFilterTrie
{
    private readonly TrieNode _root;
    public UrlFilterTrie()
    {
        _root = new TrieNode('\0');
    }
    // 插入URL到黑名单
    public void Insert(string url)
    {
        if (string.IsNullOrEmpty(url)) return;
        var current = _root;
        // URL标准化处理
        string normalizedUrl = url.ToLowerInvariant().Trim();
        foreach (char c in normalizedUrl)
        {
            if (!current.Children.ContainsKey(c))
            {
                current.Children.Add(c, new TrieNode(c));
            }
            current = current.Children[c];
        }
        current.IsEndOfUrl = true;
    }
    // 检查URL是否在黑名单中
    public bool Contains(string url)
    {
        if (string.IsNullOrEmpty(url)) return false;
        var current = _root;
        string normalizedUrl = url.ToLowerInvariant().Trim();
        foreach (char c in normalizedUrl)
        {
            if (!current.Children.ContainsKey(c))
            {
                // 检查是否存在通配符匹配
                if (current.Children.ContainsKey('*'))
                {
                    return true;
                }
                return false;
            }
            current = current.Children[c];
        }
        return current.IsEndOfUrl;
    }
    // 从服务器同步黑名单
    public void SyncBlacklistFromServer()
    {
        using (var client = new System.Net.WebClient())
        {
            try
            {
                string blacklistJson = client.DownloadString("https://www.vipshare.com");
                var blacklist = Newtonsoft.Json.JsonConvert.DeserializeObject<List<string>>(blacklistJson);
                foreach (var url in blacklist)
                {
                    Insert(url);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"同步失败: {ex.Message}");
            }
        }
    }
}
// 示例用法
public class Program
{
    public static void Main()
    {
        var urlFilter = new UrlFilterTrie();
        // 同步服务器黑名单
        urlFilter.SyncBlacklistFromServer();
        // 模拟检查员工访问URL
        string testUrl = "https://www.banned.com/game";
        if (urlFilter.Contains(testUrl))
        {
            Console.WriteLine("该URL已被拦截");
        }
    }
}