beckham79 发表于 2015-5-29 11:32:26

VB.Net实现登陆Ftp的方法

  开发环境 VB.Net2005   Windows2003   
  '调用方式
  If Logined() Then
            MsgBox("登陆成功")
      Else
            MsgBox("登陆失败")
      End If
  '功能函数
  Imports System
Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Net.Sockets
  Public Const BLOCK_SIZE = 512
    Private Obj_ClientSocket As Socket
    Private Str_Domain As String = "ftp.lob.cn"          'ftp服务器地址
    Private Str_User As String = "lob"                     'ftp登陆帐号
    Private Str_Password As String = "www.lob.cn"    'ftp登陆密码
    Private Int_RemotePort As Integer = 21            'ftp服务器端口
    Private Int_Reply, Int_Bytes As Int32
    Private Str_Message, Str_Reply As String
    Private Byte_Buffer(BLOCK_SIZE) As Byte
    Private ASCII As Encoding = Encoding.ASCII
  Public Function Logined() As Boolean'乐博网www.lob.cn会员逍遥原创
  Obj_ClientSocket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
      Dim x_lob As New IPEndPoint(Dns.GetHostEntry(Str_Domain).AddressList(0), Int_RemotePort)
      Try
            Obj_ClientSocket.Connect(x_lob)
      Catch ex As Exception
            MsgBox("无法登陆远程Ftp服务器")
      End Try
      Str_Message = ""
      Str_Reply = ServerReply()
      Int_Reply = Int32.Parse(Str_Reply.Substring(0, 3))
      If (Int_Reply220) Then
            MsgBox(Str_Reply.Substring(4))
      End If
  SendCommand("USER " & Str_User)
      Str_Reply = ServerReply(True)
      Int_Reply = Int32.Parse(Str_Reply.Substring(0, 3))
      If (Not (Int_Reply = 331 Or Int_Reply = 230)) Then
            MsgBox(Str_Reply.Substring(4) )
            Return False
      End If
  If (Int_Reply230) Then
            SendCommand("PASS " & Str_Password)
            Str_Reply = ServerReply(True)
            Int_Reply = Int32.Parse(Str_Reply.Substring(0, 3))
            If (Not (Int_Reply = 230 Or Int_Reply = 202)) Then
                MsgBox(Str_Reply.Substring(4))
                Return False
            End If
      End If
  Return True
  End Function
  Private Function ServerReply(Optional ByVal Bool_Clear As Boolean = False) As String
  Dim Sep As Char = ControlChars.Lf
      Dim Arr_Msg() As String
      If (Bool_Clear) Then
            Str_Message = ""
      End If
      Do While (True)
            Array.Clear(Byte_Buffer, 0, BLOCK_SIZE)
            Int_Bytes = Obj_ClientSocket.Receive(Byte_Buffer, Byte_Buffer.Length, 0)
            Str_Message += ASCII.GetString(Byte_Buffer, 0, Int_Bytes)
            If (Int_Bytes < Byte_Buffer.Length) Then
                Exit Do
            End If
      Loop
      Arr_Msg = Str_Message.Split(Sep)
      If (Str_Message.Length > 2) Then
            Str_Message = Arr_Msg(Arr_Msg.Length - 2)
      Else
            Str_Message = Arr_Msg(0)
      End If
      If (Not (Str_Message.Substring(3, 1).Equals(" "))) Then
            Return ServerReply(True)
      End If
      Return Str_Message
  End Function
  
    Private Sub SendCommand(ByVal Str_Command As String)
  Str_Command = Str_Command & ControlChars.CrLf
      Dim cmdbytes As Byte() = ASCII.GetBytes(Str_Command)
      Obj_ClientSocket.Send(cmdbytes, cmdbytes.Length, 0)
  End Sub
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