c# 操作 FTP 方法

using System;
using System.Net;
using System.IO;
using System.Text;
using System.Net.Sockets;

/// <summary>
/// FTPClient 的摘要说明。
/// </summary>
public class FTPClient
{
    #region 构造函数
    /// <summary>
    /// 缺省构造函数
    /// </summary>
    public FTPClient()
    {
        strRemoteHost = "";
        strRemotePath = "";
        strRemoteUser = "";
        strRemotePass = "";
        strRemotePort = 21;
        bConnected = false;
    } /// <summary>
    /// 构造函数
    /// </summary>
    /// <param name="remoteHost"></param>
    /// <param name="remotePath"></param>
    /// <param name="remoteUser"></param>
    /// <param name="remotePass"></param>
    /// <param name="remotePort"></param>
    public FTPClient(string remoteHost, string remotePath, string remoteUser, string remotePass, int remotePort)
    {
        strRemoteHost = remoteHost;
        strRemotePath = remotePath;
        strRemoteUser = remoteUser;
        strRemotePass = remotePass;
        strRemotePort = remotePort;
        Connect();
    }
    #endregion
    #region 登陆
    /// <summary>
    /// FTP服务器IP地址
    /// </summary>
    private string strRemoteHost;
    public string RemoteHost
    {
        get
        {
            return strRemoteHost;
        }
        set
        {
            strRemoteHost = value;
        }
    }
    /// <summary>
    /// FTP服务器端口
    /// </summary>
    private int strRemotePort;
    public int RemotePort
    {
        get
        {
            return strRemotePort;
        }
        set
        {
            strRemotePort = value;
        }
    }
    /// <summary>
    /// 当前服务器目录
    /// </summary>
    private string strRemotePath;
    public string RemotePath
    {
        get
        {
            return strRemotePath;
        }
        set
        {
            strRemotePath = value;
        }
    }
    /// <summary>
    /// 登录用户账号
    /// </summary>
    private string strRemoteUser;
    public string RemoteUser
    {
        set
        {
            strRemoteUser = value;
        }
    }
    /// <summary>
    /// 用户登录密码
    /// </summary>
    private string strRemotePass;
    public string RemotePass
    {
        set
        {
            strRemotePass = value;
        }
    } /// <summary>
    /// 是否登录
    /// </summary>
    private Boolean bConnected;
    public bool Connected
    {
        get
        {
            return bConnected;
        }
    }
    #endregion
    #region 链接
    /// <summary>
    /// 建立连接
    /// </summary>
    public void Connect()
    {
        socketControl = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        IPEndPoint ep = new IPEndPoint(IPAddress.Parse(RemoteHost), strRemotePort);
        // 链接
        try
        {
            socketControl.Connect(ep);
        }
        catch (Exception)
        {
            throw new IOException("Couldn't connect to remote server");
        }   // 获取应答码
        ReadReply();
        if (iReplyCode != 220)
        {
            DisConnect();
            throw new IOException(strReply.Substring(4));
        }   // 登陆
        SendCommand("USER " + strRemoteUser);
        if (!(iReplyCode == 331 || iReplyCode == 230))
        {
            CloseSocketConnect();//关闭连接
            throw new IOException(strReply.Substring(4));
        }
        if (iReplyCode != 230)
        {
            SendCommand("PASS " + strRemotePass);
            if (!(iReplyCode == 230 || iReplyCode == 202))
            {
                CloseSocketConnect();//关闭连接
                throw new IOException(strReply.Substring(4));
            }
        }
        bConnected = true;   // 切换到目录
        ChDir(strRemotePath);
    }
    /// <summary>
    /// 关闭连接
    /// </summary>
    public void DisConnect()
    {
        if (socketControl != null)
        {
            SendCommand("QUIT");
        }
        CloseSocketConnect();
    }
    #endregion
    #region 传输模式 /// <summary>
    /// 传输模式:二进制类型、ASCII类型
    /// </summary>
    public enum TransferType { Binary, ASCII }; /// <summary>
    /// 设置传输模式
    /// </summary>
    /// <param name="ttType">传输模式</param>
    public void SetTransferType(TransferType ttType)
    {
        if (ttType == TransferType.Binary)
        {
            SendCommand("TYPE I");//binary类型传输
        }
        else
        {
            SendCommand("TYPE A");//ASCII类型传输
        }
        if (iReplyCode != 200)
        {
            throw new IOException(strReply.Substring(4));
        }
        else
        {
            trType = ttType;
        }
    }
    /// <summary>
    /// 获得传输模式
    /// </summary>
    /// <returns>传输模式</returns>
    public TransferType GetTransferType()
    {
        return trType;
    }

    #endregion
    #region 文件操作
    /// <summary>
    /// 获得文件列表
    /// </summary>
    /// <param name="strMask">文件名的匹配字符串</param>
    /// <returns></returns>
    public string[] Dir(string strMask)
    {
        // 建立链接
        if (!bConnected)
        {
            Connect();
        }   //建立进行数据连接的socket
        Socket socketData = CreateDataSocket();

        //传送命令
        SendCommand("NLST " + strMask);   //分析应答代码
        if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226))
        {
            throw new IOException(strReply.Substring(4));
        }   //获得结果
        strMsg = "";
        while (true)
        {
            int iBytes = socketData.Receive(buffer, buffer.Length, 0);
            strMsg += ASCII.GetString(buffer, 0, iBytes);
            if (iBytes < buffer.Length)
            {
                break;
            }
        }
        char[] seperator = { '\n' };
        string[] strsFileList = strMsg.Split(seperator);
        socketData.Close();//数据socket关闭时也会有返回码
        if (iReplyCode != 226)
        {
            ReadReply();
            if (iReplyCode != 226)
            {
                throw new IOException(strReply.Substring(4));
            }
        }
        return strsFileList;
    }
    /// <summary>
    /// 获取文件大小
    /// </summary>
    /// <param name="strFileName">文件名</param>
    /// <returns>文件大小</returns>
    private long GetFileSize(string strFileName)
    {
        if (!bConnected)
        {
            Connect();
        }
        SendCommand("SIZE " + Path.GetFileName(strFileName));
        long lSize = 0;
        if (iReplyCode == 213)
        {
            lSize = Int64.Parse(strReply.Substring(4));
        }
        else
        {
            throw new IOException(strReply.Substring(4));
        }
        return lSize;
    }
    /// <summary>
    /// 删除
    /// </summary>
    /// <param name="strFileName">待删除文件名</param>
    public void Delete(string strFileName)
    {
        if (!bConnected)
        {
            Connect();
        }
        SendCommand("DELE " + strFileName);
        if (iReplyCode != 250)
        {
            throw new IOException(strReply.Substring(4));
        }
    }
    /// <summary>
    /// 重命名(如果新文件名与已有文件重名,将覆盖已有文件)
    /// </summary>
    /// <param name="strOldFileName">旧文件名</param>
    /// <param name="strNewFileName">新文件名</param>
    public void Rename(string strOldFileName, string strNewFileName)
    {
        if (!bConnected)
        {
            Connect();
        }
        SendCommand("RNFR " + strOldFileName);
        if (iReplyCode != 350)
        {
            throw new IOException(strReply.Substring(4));
        }
        // 如果新文件名与原有文件重名,将覆盖原有文件
        SendCommand("RNTO " + strNewFileName);
        if (iReplyCode != 250)
        {
            throw new IOException(strReply.Substring(4));
        }
    }
    #endregion
    #region 上传和下载
    /// <summary>
    /// 下载一批文件
    /// </summary>
    /// <param name="strFileNameMask">文件名的匹配字符串</param>
    /// <param name="strFolder">本地目录(不得以\结束)</param>
    public void Get(string strFileNameMask, string strFolder)
    {
        if (!bConnected)
        {
            Connect();
        }
        string[] strFiles = Dir(strFileNameMask);
        foreach (string strFile in strFiles)
        {
            if (!strFile.Equals(""))//一般来说strFiles的最后一个元素可能是空字符串
            {
                Get(strFile, strFolder, strFile);
            }
        }
    }
    /// <summary>
    /// 下载一个文件
    /// </summary>
    /// <param name="strRemoteFileName">要下载的文件名</param>
    /// <param name="strFolder">本地目录(不得以\结束)</param>
    /// <param name="strLocalFileName">保存在本地时的文件名</param>
    public void Get(string strRemoteFileName, string strFolder, string strLocalFileName)
    {
        if (!bConnected)
        {
            Connect();
        }
        SetTransferType(TransferType.Binary);
        if (strLocalFileName.Equals(""))
        {
            strLocalFileName = strRemoteFileName;
        }
        if (!File.Exists(strLocalFileName))
        {
            Stream st = File.Create(strLocalFileName);
            st.Close();
        }
        FileStream output = new
         FileStream(strFolder + "\\" + strLocalFileName, FileMode.Create);
        Socket socketData = CreateDataSocket();
        SendCommand("RETR " + strRemoteFileName);
        if (!(iReplyCode == 150 || iReplyCode == 125
         || iReplyCode == 226 || iReplyCode == 250))
        {
            throw new IOException(strReply.Substring(4));
        }
        while (true)
        {
            int iBytes = socketData.Receive(buffer, buffer.Length, 0);
            output.Write(buffer, 0, iBytes);
            if (iBytes <= 0)
            {
                break;
            }
        }
        output.Close();
        if (socketData.Connected)
        {
            socketData.Close();
        }
        if (!(iReplyCode == 226 || iReplyCode == 250))
        {
            ReadReply();
            if (!(iReplyCode == 226 || iReplyCode == 250))
            {
                throw new IOException(strReply.Substring(4));
            }
        }
    }
    /// <summary>
    /// 上传一批文件
    /// </summary>
    /// <param name="strFolder">本地目录(不得以\结束)</param>
    /// <param name="strFileNameMask">文件名匹配字符(可以包含*和?)</param>
    public void Put(string strFolder, string strFileNameMask)
    {
        string[] strFiles = Directory.GetFiles(strFolder, strFileNameMask);
        foreach (string strFile in strFiles)
        {
            //strFile是完整的文件名(包含路径)
            Put(strFile);
        }
    }
    /// <summary>
    /// 上传一个文件    已重载
    /// </summary>
    /// <param name="strFileName">包括路径 本地文件名</param>
    public void Put(string strFileName)
    {
        if (!bConnected)
        {
            Connect();
        }
        Socket socketData = CreateDataSocket();
        SendCommand("STOR " + Path.GetFileName(strFileName));
        if (!(iReplyCode == 125 || iReplyCode == 150))
        {
            throw new IOException(strReply.Substring(4));
        }
        FileStream input = new
         FileStream(strFileName, FileMode.Open);
        int iBytes = 0;
        while ((iBytes = input.Read(buffer, 0, buffer.Length)) > 0)
        {
            socketData.Send(buffer, iBytes, 0);
        }
        input.Close();
        if (socketData.Connected)
        {
            socketData.Close();
        }
        if (!(iReplyCode == 226 || iReplyCode == 250))
        {
            ReadReply();
            if (!(iReplyCode == 226 || iReplyCode == 250))
            {
                throw new IOException(strReply.Substring(4));
            }
        }
    }

    #endregion
    #region 目录操作
    /// <summary>
    /// 创建目录
    /// </summary>
    /// <param name="strDirName">目录名</param>
    public void MkDir(string strDirName)
    {
        if (!bConnected)
        {
            Connect();
        }
        SendCommand("MKD " + strDirName);
        if (iReplyCode != 257)
        {
            throw new IOException(strReply.Substring(4));
        }
    }

    /// <summary>
    /// 删除目录
    /// </summary>
    /// <param name="strDirName">目录名</param>
    public void RmDir(string strDirName)
    {
        if (!bConnected)
        {
            Connect();
        }
        SendCommand("RMD " + strDirName);
        if (iReplyCode != 250)
        {
            throw new IOException(strReply.Substring(4));
        }
    }

    /// <summary>
    /// 改变目录
    /// </summary>
    /// <param name="strDirName">新的工作目录名</param>
    public void ChDir(string strDirName)
    {
        if (strDirName.Equals(".") || strDirName.Equals(""))
        {
            return;
        }
        if (!bConnected)
        {
            Connect();
        }
        SendCommand("CWD " + strDirName);
        if (iReplyCode != 250)
        {
            throw new IOException(strReply.Substring(4));
        }
        this.strRemotePath = strDirName;
    }

    #endregion
    #region 内部变量
    /// <summary>
    /// 服务器返回的应答信息(包含应答码)
    /// </summary>
    private string strMsg;
    /// <summary>
    /// 服务器返回的应答信息(包含应答码)
    /// </summary>
    private string strReply;
    /// <summary>
    /// 服务器返回的应答码
    /// </summary>
    private int iReplyCode;
    /// <summary>
    /// 进行控制连接的socket
    /// </summary>
    private Socket socketControl;
    /// <summary>
    /// 传输模式
    /// </summary>
    private TransferType trType;
    /// <summary>
    /// 接收和发送数据的缓冲区
    /// </summary>
    private static int BLOCK_SIZE = 512;
    Byte[] buffer = new Byte[BLOCK_SIZE];
    /// <summary>
    /// 编码方式
    /// </summary>
    Encoding ASCII = Encoding.ASCII;
    #endregion
    #region 内部函数
    /// <summary>
    /// 将一行应答字符串记录在strReply和strMsg
    /// 应答码记录在iReplyCode
    /// </summary>
    private void ReadReply()
    {
        strMsg = "";
        strReply = ReadLine();
        iReplyCode = Int32.Parse(strReply.Substring(0, 3));
    } /// <summary>
    /// 建立进行数据连接的socket
    /// </summary>
    /// <returns>数据连接socket</returns>
    private Socket CreateDataSocket()
    {
        SendCommand("PASV");
        if (iReplyCode != 227)
        {
            throw new IOException(strReply.Substring(4));
        }
        int index1 = strReply.IndexOf('(');
        int index2 = strReply.IndexOf(')');
        string ipData =
         strReply.Substring(index1 + 1, index2 - index1 - 1);
        int[] parts = new int[6];
        int len = ipData.Length;
        int partCount = 0;
        string buf = "";
        for (int i = 0; i < len && partCount <= 6; i++)
        {
            char ch = Char.Parse(ipData.Substring(i, 1));
            if (Char.IsDigit(ch))
                buf += ch;
            else if (ch != ',')
            {
                throw new IOException("Malformed PASV strReply: " +
                 strReply);
            }
            if (ch == ',' || i + 1 == len)
            {
                try
                {
                    parts[partCount++] = Int32.Parse(buf);
                    buf = "";
                }
                catch (Exception)
                {
                    throw new IOException("Malformed PASV strReply: " +
                     strReply);
                }
            }
        }
        string ipAddress = parts[0] + "." + parts[1] + "." +
         parts[2] + "." + parts[3];
        int port = (parts[4] << 8) + parts[5];
        Socket s = new
         Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        IPEndPoint ep = new
         IPEndPoint(IPAddress.Parse(ipAddress), port);
        try
        {
            s.Connect(ep);
        }
        catch (Exception)
        {
            throw new IOException("Can't connect to remote server");
        }
        return s;
    }
    /// <summary>
    /// 关闭socket连接(用于登录以前)
    /// </summary>
    private void CloseSocketConnect()
    {
        if (socketControl != null)
        {
            socketControl.Close();
            socketControl = null;
        }
        bConnected = false;
    }

    /// <summary>
    /// 读取Socket返回的所有字符串
    /// </summary>
    /// <returns>包含应答码的字符串行</returns>
    private string ReadLine()
    {
        while (true)
        {
            int iBytes = socketControl.Receive(buffer, buffer.Length, 0);
            strMsg += ASCII.GetString(buffer, 0, iBytes);
            if (iBytes < buffer.Length)
            {
                break;
            }
        }
        char[] seperator = { '\n' };
        string[] mess = strMsg.Split(seperator);
        if (strMsg.Length > 2)
        {
            strMsg = mess[mess.Length - 2];
            //seperator[0]是10,换行符是由13和0组成的,分隔后10后面虽没有字符串,
            //但也会分配为空字符串给后面(也是最后一个)字符串数组,
            //所以最后一个mess是没用的空字符串
            //但为什么不直接取mess[0],因为只有最后一行字符串应答码与信息之间有空格
        }
        else
        {
            strMsg = mess[0];
        }
        if (!strMsg.Substring(3, 1).Equals(" "))//返回字符串正确的是以应答码(如220开头,后面接一空格,再接问候字符串)
        {
            return ReadLine();
        }
        return strMsg;
    }
    /// <summary>
    /// 发送命令并获取应答码和最后一行应答字符串
    /// </summary>
    /// <param name="strCommand">命令</param>
    private void SendCommand(String strCommand)
    {
        //Byte[] cmdBytes =
        // Encoding.ASCII.GetBytes((strCommand + "\r\n").ToCharArray());
        byte[] cmdBytes = Encoding.GetEncoding("gb2312").GetBytes((strCommand + "\r\n").ToCharArray());
        socketControl.Send(cmdBytes, cmdBytes.Length, 0);
        ReadReply();
    }
    #endregion

}