一、将图片存入Oracle数据库
示例表NEWS的结构为:newsid number(10),title varchar2(100),image(blob)
方法1:利用OracleCommandBuilder类(该类用于自动生成用于协调 DataSet 的更改与关联的数据库的单表命令。)
Dim cn As New OracleConnection("data source=site;uid=gf;pwd=macro;") cn.Open()
Dim da As New OracleDataAdapter("select * from news", cn) Dim myCB As New OracleCommandBuilder(da) Dim ds As New DataSet("news") da.MissingSchemaAction = MissingSchemaAction.AddWithKey Dim fs As Stream = File1.PostedFile.InputStream 'File1为文件选择框,作为服务器控件使用 Dim mydata(fs.Length) As Byte fs.Read(mydata, 0, fs.Length) fs.Close() da.Fill(ds, "news") Dim myRow As DataRow = ds.Tables("news").NewRow myRow("newsid") = txtNewsID.Text myRow("title") = txtTitle.Text myRow("image") = mydata ds.Tables("news").Rows.Add(myRow) da.Update(ds, "news")
cn.Close()
方法2:利用过程
事先定义的Oracle过程为:
CREATE OR REPLACE PROCEDURE "GF"."NEWS_ADD" (in_newsid in news.newsid%type, in_title in news.title%type, in_imag in news.image%type) as begin insert into gf.news values(in_newsid,in_title,in_image); end;
下面是将数据存入数据库的代码:
Dim cn As New OracleConnection("data source=site;uid=gf;pwd=macro;") cn.Open()
Dim cmd As New OracleCommand("news_add", cn) cmd.CommandType = CommandType.StoredProcedure cmd.Parameters.Add(New OracleParameter("in_newsid", OracleType.Number, 10)) cmd.Parameters("in_newsid").Value = txtNewsID.Text.Trim cmd.Parameters.Add(New OracleParameter("in_title", OracleType.VarChar, 100)) cmd.Parameters("in_title").Value = txtTitle.Text.Trim
Dim fs As Stream = File1.PostedFile.InputStream Dim mydata(fs.Length) As Byte '定义一个字节数组用于读取图片流 fs.Read(mydata, 0, fs.Length) fs.Close()
cmd.Parameters.Add(New OracleParameter("in_image", OracleType.Blob)) cmd.Parameters("in_image").Value = mydata
cmd.ExecuteNonQuery()
cn.Close()
二、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" 
|