从Oracle数据库中读出图片的方法（代码教程）

zhaorong · 发表于编程和数据库 2018-1-25 17:02:25


	从Oracle数据库中读出图片方法1：从数据库中读取数据并以文件形式保留在服务器上 Dim conn As New OracleClient.OracleConnection Dim cmd As New OracleClient.OracleCommand Dim myReader As OracleClient.OracleDataReader Dim sql As String Dim fl As File sql = "select * from news where newsid=3211" '从数据库中取出图片数据 blob conn.ConnectionString = "Password=macro;User ID=gf;Data Source=site" cmd.CommandText = sql cmd.Connection = conn conn.Open() myReader = cmd.ExecuteReader(CommandBehavior.SequentialAccess) myReader.Read() Label1.Text = myReader("title") Dim fs As FileStream ' Writes the BLOB to a file (.bmp). Dim bw As BinaryWriter ' Streams the binary data to the FileStream object. Dim bufferSize As Integer = 1000 ' The size of the BLOB buffer. Dim outbyte(bufferSize - 1) As Byte ' The BLOB byte() buffer to be filled by GetBytes. Dim retval As Long ' The bytes returned from GetBytes. Dim startIndex As Long = 0 ' The starting position in the BLOB output. Dim fpath As String '将图片数据存成本地文件 fpath = Server.MapPath(Request.ApplicationPath) & "\Image\photo.bmp" fs = New FileStream(fpath, FileMode.OpenOrCreate, FileAccess.Write) bw = New BinaryWriter(fs) ' Reset the starting byte for a new BLOB. startIndex = 0 ' Read bytes into outbyte() and retain the number of bytes returned. retval = myReader.GetBytes(2, startIndex, outbyte, 0, bufferSize) 'GetBytes 返回字段中的可用字节数,第一个参数为从0开始的列序号 ' Continue reading and writing while there are bytes beyond the size of the buffer. Do While retval = bufferSize bw.Write(outbyte) bw.Flush() '清理当前编写器的所有缓冲区，使所有缓冲数据写入基础设备。 ' Reposition the start index to the end of the last buffer and fill the buffer. startIndex = startIndex + bufferSize retval = myReader.GetBytes(2, startIndex, outbyte, 0, bufferSize) Loop ' Write the remaining buffer. bw.Write(outbyte) bw.Flush() ' Close the output file. bw.Close() fs.Close() ' Close the reader and the connection. myReader.Close() conn.Close() Dim logo As Image '文件格式转换 logo = Image.FromFile(fpath) fpath = Server.MapPath(Request.ApplicationPath) & "\Image\zkjhy.jpeg" logo.Save(fpath, System.Drawing.Imaging.ImageFormat.Jpeg) 'Me.Image1.Width = New Unit(300) '调整显示大小 'Me.Image1.Height = New Unit(350) Me.Image1.ImageUrl = "image/zkjhy.jpeg" 复制代码*

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从Oracle数据库中读出图片的方法（代码教程）

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