数据库Image类型写入文本文件及文本文件写入数据库Image

 

  

 

 
#region 数据库表中Image类型（二进制）写入文本文件
 protected void Button1_Click(object sender, EventArgs e)
    {
        string arg_msg = "";
        string str = "";

        string ls_sql = "select * from r3_oa_image where billid=2";
        DataTable dt = cs_con.Select(ls_sql, null, ref arg_msg).Tables[0];
        if (dt.Rows.Count > 0)
        {
            string add_file = "";
            string file_name = "";
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                byte[] image = (byte[])dt.Rows[i]["add_file"];//其中add_file字段是Image类型
                StringBuilder lkj = new StringBuilder();
                for (int k = 0; k < image.Length; k++)
                {
                    lkj.Append("," + image[k].ToString().Trim());
                }
               //导入到文本文件
                string filename = @"d:\test.txt";
              FileInfo fileinfo = new FileInfo(filename);
              using (FileStream fs = fileinfo.OpenWrite())
              {
                    StreamWriter sw = new StreamWriter(fs);
                    sw.BaseStream.Seek(0, SeekOrigin.End);
                    sw.Write(lkj);
                    sw.Flush();
                    sw.Close();
              }
            }
        }
    }
#endregion 

 

 

#region  文本文件转换成二进制存入数据库
protected void Button2_Click(object sender, EventArgs e)
    {

        string filename = @"d:\test.txt";
        StreamReader sr = new StreamReader(filename, System.Text.Encoding.Default);
        String lkj = sr.ReadToEnd();
        sr.Close();
        string[] strs = lkj.ToString().Trim(',').Split(',');
        byte[] textByte = new byte[35811];
        for (int j = 0; j < 951296; j++)//这里的951296是前面方法中image.length，这里有点BUG获取不到大小，使用byte数组定义大小，
        {
            textByte[j] = Convert.ToByte(strs[j]);
        }
        SqlConnection con = cs_con.DBconn();
        SqlCommand command = new SqlCommand();
        command.Connection = con;
        command.CommandText = "insert into r3_oa_image(billid,add_file,upload_time,file_name,remark) values(1,@add_file,getdate(),'npActiveXFirefox4x.xpi','打印控件');";
        command.Parameters.Add("@add_file", SqlDbType.Image, textByte.Length, "add_file");
        command.Parameters["@add_file"].Value = textByte;
        con.Open();
        command.ExecuteNonQuery();
        con.Close();

    }
#endregion 

 

 下载：

 

 

 protected void Button3_Click(object sender, EventArgs e)
    {
        string arg_msg = "";
        if (!file_down("1", ref arg_msg))
        {
            ScriptManager.RegisterStartupScript(this, this.GetType(), "js", "alert('" + arg_msg.ToString().Trim() + "');", true);
        }
    }


    #region 文件下载
    private bool file_down(string bill, ref string arg_msg)
    {
        bool rslt = true;
        try
        {
            if (bill == null && bill.Trim().Length > 0)
            {
                rslt = false;
                arg_msg = "下载失败";
                goto ext_file_down;
            }

            Byte[] bytes;
            string ls_down_file = "select * from r3_oa_image WHERE  billid=" + bill;
            DataTable dt = cs_con.Select(ls_down_file, null, ref arg_msg).Tables[0];
            bytes = (Byte[])(dt.Rows[0]["add_file"]);
            string fileName = dt.Rows[0]["file_name"].ToString().Trim();
            Response.ClearContent();
            Response.ClearHeaders();
            Response.ContentType = "application/octet-stream";  // 设置输出流的Http MIME类型//通知浏览器下载文件而不是打开
            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8)); //fileName为需要下载的文件名
            Response.BinaryWrite(bytes);  // 写入输入流
            Response.Flush();  // 向客户端发送数据流
            Response.End();
        }
        catch (Exception ex_file_down)
        {
            rslt = false;
            arg_msg = "下载失败:" + ex_file_down.Message;
            goto ext_file_down;
        }
    ext_file_down: ;
        return rslt;
    }
    #endregion

 

 数据库表中IMAGE类型字段的内容写入到txt文档（即文本文件）Button1_Click

用户也可以从写入的文本文件通过Button2_Click的方法写入数据库

用户功能下载：Button3_Click的内容

 

主要是如下一个 Setup_online.msi上传到数据库，保存至add_file字段

通过button1的方法把add_file字段的内容写入test.txt文本文件，并保存，

 如果某个程序需要Setup_online.msi的内容，即只要拷贝test.txt文件，通过button2即可，上传至数据库

然后通过下载功能既可以得到Setup_online.msi的文件