FTP是一个8位的客户端-服务器协议，能操作任何类型的文件而不需要进一步处理，就像MIME或Unicode一样。可以通过C#中的FtpWebRequest类、NetworkCredential类、WebRequestMethods类来实现一个FTP操作的相关辅助类FTPHelper。
先来看MSDN关于上述几个类的定义以及解释：
FtpWebRequest类：实现文件传输协议 (FTP) 客户端。若要获取的实例FtpWebRequest，使用Create方法。 此外可以使用WebClient类来上传和下载信息从 FTP 服务器。 使用任一种方法，当您指定使用 FTP 方案的网络资源 (例如， "ftp://contoso.com")FtpWebRequest类提供了能够以编程方式与 FTP 服务器进行交互。
NetworkCredential类：为基于密码的身份验证方案（如基本、摘要式、NTLM 和 Kerberos 身份验证）提供凭据。
WebRequestMethods类：WebRequestMethods.Ftp、WebRequestMethods.File 和 WebRequestMethods.Http 类的容器类。 无法继承此类。
封装好的FTPHelper帮助类如下，包含连接FTP服务器、上传文件到FTP服务器、下载FTP服务器文件、删除FTP服务器文件、获取当前目录下明细等几个常用方法。具体实现如下：
public class FTPHelper
{
#region 字段
string ftpURI;
string ftpUserID;
string ftpServerIP;
string ftpPassword;
string ftpRemotePath;
#endregion
/// <summary>
/// 连接FTP服务器
/// </summary>
/// <param name="FtpServerIP">FTP连接地址</param>
/// <param name="FtpRemotePath">指定FTP连接成功后的当前目录, 如果不指定即默认为根目录</param>
/// <param name="FtpUserID">用户名</param>
/// <param name="FtpPassword">密码</param>
public FTPHelper(string FtpServerIP, string FtpRemotePath, string FtpUserID, string FtpPassword)
{
ftpServerIP = FtpServerIP;
ftpRemotePath = FtpRemotePath;
ftpUserID = FtpUserID;
ftpPassword = FtpPassword;
ftpURI = "ftp://" + ftpServerIP + "/" + ftpRemotePath + "/";
}
/// <summary>
/// 上传
/// </summary>
public void Upload(string filename)
{
FileInfo fileInf = new FileInfo(filename);
FtpWebRequest reqFTP;
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + fileInf.Name));
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
reqFTP.Method = WebRequestMethods.Ftp.UploadFile;
reqFTP.KeepAlive = false;
reqFTP.UseBinary = true;
reqFTP.ContentLength = fileInf.Length;
int buffLength = ;
byte[] buff = new byte[buffLength];
int contentLen;
FileStream fs = fileInf.OpenRead();
try
{
Stream strm = reqFTP.GetRequestStream();
contentLen = fs.Read(buff, , buffLength);
while (contentLen != )
{
strm.Write(buff, , contentLen);
contentLen = fs.Read(buff, , buffLength);
}
strm.Close();
fs.Close();
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 下载
/// </summary>
public void Download(string filePath, string fileName)
{
try
{
FileStream outputStream = new FileStream(filePath + "\\" + fileName, FileMode.Create);
FtpWebRequest reqFTP;
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + fileName));
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
reqFTP.UseBinary = true;
FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
Stream ftpStream = response.GetResponseStream();
long cl = response.ContentLength;
int bufferSize = ;
int readCount;
byte[] buffer = new byte[bufferSize];
readCount = ftpStream.Read(buffer, , bufferSize);
while (readCount > )
{
outputStream.Write(buffer, , readCount);
readCount = ftpStream.Read(buffer, , bufferSize);
}
ftpStream.Close();
outputStream.Close();
response.Close();
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 删除文件
/// </summary>
public void Delete(string fileName)
{
try
{
FtpWebRequest reqFTP;
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + fileName));
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
reqFTP.Method = WebRequestMethods.Ftp.DeleteFile;
reqFTP.KeepAlive = false;
string result = String.Empty;
FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
long size = response.ContentLength;
Stream datastream = response.GetResponseStream();
StreamReader sr = new StreamReader(datastream);
result = sr.ReadToEnd();
sr.Close();
datastream.Close();
response.Close();
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 获取当前目录下明细(包含文件和文件夹)
/// </summary>
public string[] GetFilesDetailList()
{
try
{
StringBuilder result = new StringBuilder();
FtpWebRequest ftp;
ftp = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI));
ftp.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
ftp.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
WebResponse response = ftp.GetResponse();
StreamReader reader = new StreamReader(response.GetResponseStream());
string line = reader.ReadLine();
line = reader.ReadLine();
line = reader.ReadLine();
while (line != null)
{
result.Append(line);
result.Append("\n");
line = reader.ReadLine();
}
result.Remove(result.ToString().LastIndexOf("\n"), );
reader.Close();
response.Close();
return result.ToString().Split('\n');
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
/// <summary>
/// 获取FTP文件列表(包括文件夹)
/// </summary>
private string[] GetAllList(string url)
{
List<string> list = new List<string>();
FtpWebRequest req = (FtpWebRequest)WebRequest.Create(new Uri(url));
req.Credentials = new NetworkCredential(ftpPassword, ftpPassword);
req.Method = WebRequestMethods.Ftp.ListDirectory;
req.UseBinary = true;
req.UsePassive = true;
try
{
using (FtpWebResponse res = (FtpWebResponse)req.GetResponse())
{
using (StreamReader sr = new StreamReader(res.GetResponseStream()))
{
string s;
while ((s = sr.ReadLine()) != null)
{
list.Add(s);
}
}
}
}
catch (Exception ex)
{
throw (ex);
}
return list.ToArray();
}
/// <summary>
/// 获取当前目录下文件列表(不包括文件夹)
/// </summary>
public string[] GetFileList(string url)
{
StringBuilder result = new StringBuilder();
FtpWebRequest reqFTP;
try
{
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(url));
reqFTP.UseBinary = true;
reqFTP.Credentials = new NetworkCredential(ftpPassword, ftpPassword);
reqFTP.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
WebResponse response = reqFTP.GetResponse();
StreamReader reader = new StreamReader(response.GetResponseStream());
string line = reader.ReadLine();
while (line != null)
{
if (line.IndexOf("<DIR>") == -)
{
result.Append(Regex.Match(line, @"[\S]+ [\S]+", RegexOptions.IgnoreCase).Value.Split(' ')[]);
result.Append("\n");
}
line = reader.ReadLine();
}
result.Remove(result.ToString().LastIndexOf('\n'), );
reader.Close();
response.Close();
}
catch (Exception ex)
{
throw (ex);
}
return result.ToString().Split('\n');
}
/// <summary>
/// 判断当前目录下指定的文件是否存在
/// </summary>
/// <param name="RemoteFileName">远程文件名</param>
public bool FileExist(string RemoteFileName)
{
string[] fileList = GetFileList("*.*");
foreach (string str in fileList)
{
if (str.Trim() == RemoteFileName.Trim())
{
return true;
}
}
return false;
}
/// <summary>
/// 创建文件夹
/// </summary>
public void MakeDir(string dirName)
{
FtpWebRequest reqFTP;
try
{
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + dirName));
reqFTP.Method = WebRequestMethods.Ftp.MakeDirectory;
reqFTP.UseBinary = true;
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
Stream ftpStream = response.GetResponseStream();
ftpStream.Close();
response.Close();
}
catch (Exception ex)
{ }
}
/// <summary>
/// 获取指定文件大小
/// </summary>
public long GetFileSize(string filename)
{
FtpWebRequest reqFTP;
long fileSize = ;
try
{
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + filename));
reqFTP.Method = WebRequestMethods.Ftp.GetFileSize;
reqFTP.UseBinary = true;
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
Stream ftpStream = response.GetResponseStream();
fileSize = response.ContentLength;
ftpStream.Close();
response.Close();
}
catch (Exception ex)
{ }
return fileSize;
}
/// <summary>
/// 更改文件名
/// </summary>
public void ReName(string currentFilename, string newFilename)
{
FtpWebRequest reqFTP;
try
{
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + currentFilename));
reqFTP.Method = WebRequestMethods.Ftp.Rename;
reqFTP.RenameTo = newFilename;
reqFTP.UseBinary = true;
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
Stream ftpStream = response.GetResponseStream();
ftpStream.Close();
response.Close();
}
catch (Exception ex)
{ }
}
/// <summary>
/// 移动文件
/// </summary>
public void MovieFile(string currentFilename, string newDirectory)
{
ReName(currentFilename, newDirectory);
}
/// <summary>
/// 切换当前目录
/// </summary>
/// <param name="IsRoot">true:绝对路径 false:相对路径</param>
public void GotoDirectory(string DirectoryName, bool IsRoot)
{
if (IsRoot)
{
ftpRemotePath = DirectoryName;
}
else
{
ftpRemotePath += DirectoryName + "/";
}
ftpURI = "ftp://" + ftpServerIP + "/" + ftpRemotePath + "/";
}
}
备注：此文章转载自C#工具类：FTP操作辅助类FTPHelper_IT技术小趣屋。
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