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_Reply <> 220) 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_Reply <> 230) 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