思路：从Blob字段中获取byte数组，然后将byte数组输出到客户端，注意设置网页的Header
代码如下：
1 string constr = System.Configuration.ConfigurationManager.ConnectionStrings["constr"].ConnectionString; 2 string sqlstr = "select file_name,FILECONTENT from fjg_file_manage where numbers='" + FileNum + "'"; 3 OracleConnection conn = new OracleConnection(constr); 4 OracleCommand cmd = new OracleCommand(sqlstr, conn); 5 6 conn.Open(); 7 OracleDataReader dr = cmd.ExecuteReader(); 8 dr.Read(); 9 //由于文件名中有空格，下载后空格会变成加号（+），因此需要进行特殊处理 10 string fileName = HttpUtility.UrlEncode(fileName,Encoding.UTF8); //编码后空格会变成加号 11 fileName = fileName.Replace("+", "%20"); //将加号替换为空格 12 //一定要设置好header，不然网页中不会弹出下载框 13 HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + fileName); 14 HttpContext.Current.Response.ContentType = "application/octet-stream"; 15 context.Response.BinaryWrite((byte[])dr["FILECONTENT"]); 16 conn.Close();