C# 实现一个简单的 FTP 客户端

摘要：FTP（File Transfer Protocol，文件传输协议）是一种用于在客户端和服务器之间传输文件的标准网络协议。使用C#编程语言，我们可以轻松实现一个FTP客户端。本文将探讨如何实现基本的FTP功能，包括连接FTP服务器、上传和下载文件。

FTP（File Transfer Protocol，文件传输协议）是一种用于在客户端和服务器之间传输文件的标准网络协议。使用C#编程语言，我们可以轻松实现一个FTP客户端。本文将探讨如何实现基本的FTP功能，包括连接FTP服务器、上传和下载文件。

以下是一个简单的C# FTP客户端示例，它展示了如何连接到FTP服务器并进行文件上传和下载操作。

using System;using System.IO;using System.Net;public class SimpleFtpClient{private string _ftpServer;private string _userName;private string _password;public SimpleFtpClient(string ftpServer, string userName, string password){_ftpServer = ftpServer;_userName = userName;_password = password;}/// /// 上传文件到FTP服务器/// ///

本地文件路径

///

服务器文件路径

public void UploadFile(string filePath, string ftpPath){FileInfo fileInf = new FileInfo(filePath);string uri = "ftp://" + _ftpServer + "/" + ftpPath;// 创建FTP请求FtpWebRequest request = (FtpWebRequest)WebRequest.Create(uri);request.Method = WebRequestMethods.Ftp.UploadFile;// 登录凭证request.Credentials = new NetworkCredential(_userName, _password);// 上传文件using (FileStream fileStream = fileInf.OpenRead){using (Stream requestStream = request.GetRequestStream){byte buffer = new byte[2048];int bytesRead;while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0){requestStream.Write(buffer, 0, bytesRead);}}}// 获取FTP服务器响应using (FtpWebResponse response = (FtpWebResponse)request.GetResponse){Console.WriteLine($"Upload File Complete, status {response.StatusDescription}");}}/// /// 从FTP服务器下载文件/// ///

服务器文件路径

///

本地保存路径

public void DownloadFile(string ftpPath, string localPath){string uri = "ftp://" + _ftpServer + "/" + ftpPath;// 创建FTP请求FtpWebRequest request = (FtpWebRequest)WebRequest.Create(uri);request.Method = WebRequestMethods.Ftp.DownloadFile;// 登录凭证request.Credentials = new NetworkCredential(_userName, _password);// 下载文件using (FtpWebResponse response = (FtpWebResponse)request.GetResponse){using (Stream responseStream = response.GetResponseStream){using (FileStream localFileStream = new FileStream(localPath, FileMode.Create)){byte buffer = new byte[2048];int bytesRead;while ((bytesRead = responseStream.Read(buffer, 0, buffer.Length)) != 0){localFileStream.Write(buffer, 0, bytesRead);}}}Console.WriteLine($"Download Complete, status {response.StatusDescription}");}}}private void btnUpload_Click(object sender, EventArgs e){OpenFileDialog openFileDialog1 = new OpenFileDialog;openFileDialog1.Filter = "All files (*.*)|*.*";openFileDialog1.Title = "Select a file to upload";if (openFileDialog1.ShowDialog == DialogResult.OK){string filename = openFileDialog1.FileName;FileInfo fileInfo = new FileInfo(filename);SimpleFtpClient ftpHelper = new SimpleFtpClient("127.0.0.1:21", "admin", "123456");ftpHelper.UploadFile(filename, fileInfo.Name);MessageBox.Show("File uploaded successfully!");}}private void btnDownload_Click(object sender, EventArgs e){SimpleFtpClient ftpHelper = new SimpleFtpClient("127.0.0.1:21", "admin", "123456");SaveFileDialog saveFileDialog=new SaveFileDialog;saveFileDialog.Filter = "All files (*.*)|*.*";saveFileDialog.Title = "Select a file to download";if (saveFileDialog.ShowDialog == DialogResult.OK){string filename = saveFileDialog.FileName;ftpHelper.DownloadFile("1724843803807.png", filename);MessageBox.Show("File downloaded successfully!");}}/// /// 列出FTP服务器上指定路径的文件和目录/// ///

服务器路径

public List ListDirectory(string path){string uri = "ftp://" + _ftpServer + "/" + path;List lst = new List;// 创建FTP请求FtpWebRequest request = (FtpWebRequest)WebRequest.Create(uri);request.Method = WebRequestMethods.Ftp.ListDirectoryDetails;// 登录凭证request.Credentials = new NetworkCredential(_userName, _password);// 获取服务器响应using (FtpWebResponse response = (FtpWebResponse)request.GetResponse){using (Stream responseStream = response.GetResponseStream){// 使用特定编码读取流，这里使用UTF8编码using (StreamReader reader = new StreamReader(responseStream, Encoding.GetEncoding("GB2312"))){string line;while ((line = reader.ReadLine) != null){lst.Add(line);}}} }return lst;}