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如何用命名管道實現局域網上兩臺主機間的文件拷貝

能實現局域網上兩臺主機間文件拷貝的方法有很多種,這裏介紹的“命名管道”(Named Pipe )是壹種比較可靠的進程間通信機制,可用在同壹臺計算機不同進程間,也可用在不同計算機的不同進程間,可以是單向的,也可以是雙向的,Windows NT、Windows 2000、Windows 95和Windows 98均提供了對它的支持,而且在Unix下也有類似的概念。它是在Microsoft LAN管理器和IBMLAN服務器網絡操作系統上實現的。

命名管道使用了MSNP(微軟網絡提供者)重定向器,這樣應用程序便可以不用了解網絡協議的細節而利用該機制實現網絡上的數據傳輸。它采用“命名管道文件系統”(Named Pipe File System)接口,其命名是采用UNC(通用命名規範)格式的:

\\ServerName\Pipe\[pipename]

\\ServerName指明命名管道是在那個服務器上創建的,ServerName既可以是壹個實際的計算機名,也可以是小數點(“.”)以指明是在本機上創建;\Pipe是壹個硬編碼(Hardcode)不用區分大小寫的字符串用以指明這是壹個管道名,該文件名從屬於NPFS;[pipename]是實際的自定義的管道名,該名稱在前面指定的服務器上必須是唯壹的,該名稱可以包含多級目錄,但目錄名必須不是已經創建的管道名,例:

\\.\Pipe\xyPipe’這是壹個合法管道名

\\.\Pipe\xyPipe\Pipe’這不是壹個合法的管道名,因為前面的目錄\\.\Pipe\xyPipe是壹個已經創建的管道名了。

\\.\Pipe\xxyPipe\Pipe’這也是壹個合法的文件名

命名管道有兩種基本通信模式:字節模式和消息模式。在字節模式中,數據是以字節流的形式在管道種傳輸,數據之間沒有邊界,在管道寫入和讀出操作中是以字節流即數據塊為基本單位操作的,這適合傳輸大容量數據;在消息模式中,數據是以壹條條不連續的消息為基本傳輸單元,消息和消息之間有邊界,在管道寫入和讀出操作中也是以消息為單位進行操作的,這種方式適合傳輸量小的數據。因為現在的文件大小常常有幾百K甚至更大,所以程序中選擇使用字節模式。

下面詳細介紹壹下CreateNamedPipe()這個函數,該函數C原型如下:

HANDLE CreateNamedPipe(

LPCTSTR lpName, // pointer to pipe name

DWORD dwOpenMode, // pipe open mode

DWORD dwPipeMode, // pipe-specific modes

DWORD nMaxInstances, // maximum number of instances

DWORD nOutBufferSize, // output buffer size, in bytes

DWORD nInBufferSize, // input buffer size, in bytes

DWORD nDefaultTimeOut, // time-out time, in milliseconds

LPSECURITY_ATTRIBUTES lpSecurityAttributes // pointer to security attributes

);

lpName:為前面所述的命名管道名。

dwOpenMode:為命名管道打開的模式,有PIPE_ACCESS_DUMPLEX(雙向)、PIPE_ACCESS_INBOUND(輸入)、PIPE_ACCESS_OUTBOUND(輸出)這三種,這些標誌還可以和壹些附加的I/O控制和安全模式的常數組合使用,詳細可參考MSDN。

dwPipeMode:為管道傳輸模式,有前面所述的PIPE_TYPE_BYTE(字節模式)和PIPE_TYPE_MESSAGE(消息模式)兩種,可以和PIPE_READMODE_BYTE和PIPE_READMODE_MESSAGE常數組合使用以限定客戶端的讀取模式。可以使用PIPE_TYPE_MESSAGE 和 PIPE_READMODE_BYTE組合來指定發送者以消息模式向管道發送數據,而接收者壹次可以讀取任意數量的字節。註意不可將PIPE_TYPE_BYTE和PIPE_READMODE_MESSAGE組合使用,這樣會導致CreateNamedPipe()函數調用失敗,因為字節模式沒有邊界,在接收端用消息模式讀取的時候無法判斷消息的邊界。

nMaxInstances:管道最大的連接實例句柄,其範圍在1到255之間。

nOutBufferSize和nInBufferSize分別指明管道輸出和輸入緩沖區的大小,如設為0則使用系統默認大小。

nDefaultTimeOut以毫秒為單位設定客戶機等待同命名管道建立連接的最長時間。

LpSecurityAttruibutes為壹個安全描述符,設為Null表示使用系統默認的描述符,同時句柄不可繼承。

要註意的是在程序中命名管道的寫操作中壹次最大只能寫64K字節的數據,

下面是服務器端程序:

(模塊中):

Public Declare Function CreateNamedPipe Lib "kernel32" Alias "CreateNamedPipeA" (ByVal lpName As String, ByVal dwOpenMode As Long, ByVal dwPipeMode As Long, ByVal nMaxInstances As Long, ByVal nOutBufferSize As Long, ByVal nInBufferSize As Long, ByVal nDefaultTimeOut As Long, ByVal lpSecurityAttributes As Long) As Long

Public Declare Function ConnectNamedPipe Lib "kernel32" (ByVal hNamedPipe As Long, ByVal lplong As Long) As Long

Public Declare Function ReadFile Lib "kernel32" (ByVal hFile As Long, lpBuffer As Any, ByVal nNumberOfBytesToRead As Long, lpNumberOfBytesRead As Long, ByVal lplong As Long) As Long

Public Declare Function WriteFile Lib "kernel32" (ByVal hFile As Long, lpBuffer As Any, ByVal nNumberOfBytesToWrite As Long, lpNumberOfBytesWritten As Long, ByVal lplong As Long) As Long

Public Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

Public Declare Function WaitNamedPipe Lib "kernel32" Alias "WaitNamedPipeA" (ByVal lpNamedPipeName As String, ByVal nTimeOut As Long) As Long

Public Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, ByVal lpSecurityAttributes As Long, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long

Public Declare Function DisconnectNamedPipe Lib "kernel32" (ByVal hNamedPipe As Long) As Long

Public Declare Function GetFileSize Lib "kernel32" (ByVal hFile As Long, lpFileSizeHigh As Long) As Long Public Const PIPE_ACCESS_DUPLEX = &H3

Public Const PIPE_ACCESS_INBOUND = &H1

Public Const PIPE_ACCESS_OUTBOUND = &H2

Public Const PIPE_CLIENT_END = &H0

Public Const PIPE_NOWAIT = &H1

Public Const PIPE_READMODE_BYTE = &H0

Public Const PIPE_READMODE_MESSAGE = &H2

Public Const PIPE_SERVER_END = &H1

Public Const PIPE_TYPE_BYTE = &H0

Public Const PIPE_TYPE_MESSAGE = &H4

Public Const PIPE_UNLIMITED_INSTANCES = 255

Public Const PIPE_WAIT = &H0

Public Const FILE_SHARE_READ = &H1

Public Const FILE_SHARE_WRITE = &H2

Public Const GENERIC_READ = &H80000000

Public Const GENERIC_WRITE = &H40000000

Public Const GENERIC_EXECUTE = &H20000000

Public Const GENERIC_ALL = &H10000000

Public Const OPEN_EXISTING = 3

Public Const ERROR_PIPE_BUSY = 231&

Public Const ERROR_PIPE_CONNECTED = 535&

Public Const ERROR_PIPE_LISTENING = 536&

Public Const ERROR_PIPE_NOT_CONNECTED = 233&

Public Const ERROR_NO_DATA = 232& Public Const BufferSize& = 51200

Public hNamePipe&, hFile&, strNamePipe$ Form中有三個按鈕,分別是“創建命名管道”(CreateNPipe)、“發送文件”(SendFile)、“關閉命名管道”(CloseNamePipe),窗口中還有壹個CommonDialog控件,命名為“CDlg1”。Form中代碼:

Dim outBuffer() As Byte, inBuffer() As Byte, BytesRead As Long, BytesWrite As Long, BytesReaded As Long, BytesWrited As Long

Private Sub CloseNamePipe_Click()

DisconnectNamedPipe hNamePipe

CloseHandle hNamePipe

CreateNPipe.Enabled = True

SendFile.Enabled = False

CloseNamePipe.Enabled = False

End Sub Private Sub CreateNPipe_Click()

Dim hReturn&

strNamePipe = "\\.\pipe\xyvanPipe"

hNamePipe = CreateNamedPipe(strNamePipe, PIPE_ACCESS_DUPLEX, PIPE_TYPE_BYTE Or PIPE_READMODE_BYTE, 1, 0, 0, 0, 0)

If hNamePipe <> -1 Then

hReturn = ConnectNamedPipe(hNamePipe, 0)

If hReturn = 0 Then

MsgBox "管道無法等待客戶端的連接!", vbInformation Or vbOKOnly

Unload Me

Else

Label1 = "已同客戶機連接上!"

End If

CreateNPipe.Enabled = False

SendFile.Enabled = True

CloseNamePipe.Enabled = True

Else

MsgBox "無法創建命名管道!", vbInformation Or vbOKOnly

Unload Me

End If

End Sub Private Sub Form_Load()

With CDlg1

.CancelError = True

.DialogTitle = "請選擇要傳輸的文件:"

.filename = ""

.Filter = "所有文件(*.*)|*.*"

.Flags = cdlOFNExplorer Or cdlOFNFileMustExist Or cdlOFNPathMustExist

.InitDir = "d:\"

End With

SendFile.Enabled = False

CloseNamePipe.Enabled = False

End Sub Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)

DisconnectNamedPipe hNamePipe

CloseHandle hFile

CloseHandle hNamePipe

End Sub Private Sub SendFile_Click()

On Error Resume Next

Dim strFileName$, lpFileSize&, lpFileSizeHigh&, lpFileSizeLeast&, byteEnd() As Byte

Dim strShortName$

CDlg1.ShowOpen

If Err.Number = 32755 Then Exit Sub

strFileName = CDlg1.filename

strShortName = CDlg1.FileTitle

hFile = CreateFile(strFileName, GENERIC_READ, FILE_SHARE_READ Or FILE_SHARE_WRITE, 0, OPEN_EXISTING, 0, 0)

If hFile = -1 Then

MsgBox "無法打開文件" & strFileName, vbInformation Or vbOKOnly

Exit Sub

End If

lpFileSize = GetFileSize(hFile, lpFileSizeHigh)

If lpFileSize = 0 Then

MsgBox "該文件大小為零,不用發送!", vbInformation Or vbOKOnly

CloseHandle hFile

Exit Sub

End If

lpFileSizeLeast = lpFileSize byteEnd() = StrConv(strShortName, vbFromUnicode)

ReDim outBuffer(UBound(byteEnd))

ByteCopy byteEnd, outBuffer

WriteFile hNamePipe, byteEnd(0), UBound(byteEnd) + 1, BytesWrited, 0 '發送短文件名

ReDim inBuffer(5)

ReadFile hNamePipe, inBuffer(0), 6, BytesReaded, 0 '讀取客戶端對話信息

If StrConv(inBuffer, vbUnicode) = "Cancel" Then

MsgBox "客戶端保存時選擇了取消,發送終止!", vbInformation Or vbOKOnly

CloseHandle hFile

Exit Sub

End If

Label1.Caption = "正在傳輸中…"

While lpFileSize > 0

If lpFileSize > BufferSize Then

ReDim outBuffer(BufferSize - 1)

ReadFile hFile, outBuffer(0), BufferSize, BytesReaded, 0

WriteFile hNamePipe, outBuffer(0), BytesReaded, BytesWrited, 0

Else

ReDim outBuffer(lpFileSize - 1)

ReadFile hFile, outBuffer(0), lpFileSize, BytesReaded, 0

WriteFile hNamePipe, outBuffer(0), lpFileSize, BytesWrited, 0

End If

lpFileSize = lpFileSize - BytesReaded

ReadFile hNamePipe, inBuffer(0), 6, BytesReaded, 0

Wend byteEnd() = StrConv("EOF", vbFromUnicode)

ReDim outBuffer(UBound(byteEnd))

ByteCopy byteEnd, outBuffer

WriteFile hNamePipe, outBuffer(0), 3, BytesWrited, 0

CloseHandle hFile

Label1 = "傳送文件完畢!"

End Sub

Public Sub ByteCopy(bySrc() As Byte, byDes() As Byte)

Dim I As Long

For i = LBound(bySrc) To UBound(bySrc)

byDes(i) = bySrc(i)

Next

End Sub 剩下的妳加我QQ我發肥妳給妳83989024

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