数据库与文件路径：附件上传下载实践-优快云博客

本文链接：https://blog.youkuaiyun.com/limengqiang/article/details/932736

本文探讨了两种附件上传下载的方式：一是通过数据库存储，包括上传至数据库的代码示例和从数据库下载的方法；二是采用文件路径保存，详细介绍了如何将附件保存至指定路径，并直接从路径读取附件内容。

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一、数据库方式：

上传至数据库代码：

代码片段：
string StencilName = this.UploadFile.PostedFile.FileName.ToString();
StencilName = StencilName.Substring(StencilName.LastIndexOf("//") + 1, StencilName.Length - StencilName.LastIndexOf("//") - 1);
tcModel.FileName = StencilName;
Byte[] StencilEntity = new byte[this.UploadFile.PostedFile.ContentLength];
this.UploadFile.PostedFile.InputStream.Read(StencilEntity, 0, this.UploadFile.PostedFile.ContentLength);
tcModel.FileEntity = StencilEntity;

从数据库下载：

代码片段：
string SeqNum = this.Request["SeqNum"].ToString();
string AttName = "";
string strSelect = "select FileName,FileEntity from TechnicContent where TecId="" + SeqNum + """;
IDataReader myReader = cSqlHelper.ExecuteReader(strSelect);
int bufferSize = 30000; // Size of the BLOB buffer.
byte[] outbyte = new byte[bufferSize]; // The BLOB byte[] buffer to be filled by GetBytes.
long retval; // The bytes returned from GetBytes.
long startIndex = 0; // The starting position in the BLOB output.
//string pub_id = ""; // The publisher id to use in the file name.
this.Response.Clear();
this.Response.ContentType = "application/x-msdownload";
this.Response.ContentEncoding = Encoding.Default;
while (myReader.Read())
{
// Get the publisher id, which must occur before getting the logo.
AttName = myReader.GetString(0);
//this.Response.AddHeader("Content-disposition","attachment;StencilName="+ Encoding.Default.GetString(Encoding.Unicode.GetBytes(StencilName)));
this.Response.AddHeader("Content-disposition", "attachment;filename=" + HttpUtility.UrlEncode(AttName));
// Read the bytes into outbyte[] and retain the number of bytes returned.
retval = myReader.GetBytes(1, startIndex, outbyte, 0, bufferSize);
this.Response.BinaryWrite(outbyte);
// Continue reading and writing while there are bytes beyond the size of the buffer.
while (retval == bufferSize)
{

// Reposition the start index to the end of the last buffe0r and fill the buffer.
startIndex += bufferSize;
retval = myReader.GetBytes(1, startIndex, outbyte, 0, bufferSize);
this.Response.BinaryWrite(outbyte);
}
}
this.Response.End();
// Close the reader and the connection.
myReader.Close();

一、文件路径方式：

保存至路径：

代码片段：

        // 灾情图片
        // 先判断上传的图片大小应该小于100k，把图片存到image文件夹的Disaster里面，表里只存图片名称
        string fullName = this.UploadFile.PostedFile.FileName; // 得到文件名称
        string exeName = string.Empty;
        if (fullName != string.Empty)
        {
            if (this.UploadFile.PostedFile.ContentLength > 102400)
            {
                Response.Write(Common.CommonClass.ShowMessageBox("请选择小于100k的照片"));
                return;
            }
            exeName = fullName.Substring(fullName.LastIndexOf(".") + 1);
            if (exeName == "jpg" || exeName == "bmp" || exeName == "gif" || exeName == "JPG" || exeName == "BMP" || exeName == "GIF")
            {
            }
            else
            {
                Response.Write(Common.CommonClass.ShowMessageBox("只能上传jpg,gif,bmp格式的文件!!!"));
                return;
            }
            Guid gid = new Guid();
            string fullimageurl = Request.MapPath("~//images//Disaster").ToString() + "//" + gid.ToString() + "." + exeName;
            HttpPostedFile postedFile = this.UploadFile.PostedFile; //得到要上传文件
            Common.CommonClass.SaveFile(postedFile, fullimageurl);
            model.Pictrue = gid.ToString() + "." + exeName;
        }