图片上传到数据库，再写入文件后下载

来源：互联网发布：二次开发软件著作权编辑：程序博客网时间：2024/05/08 09:09

图片上传到数据库，在写入文件后下载

建立一个数据库和表:
1. --创建存储图片的数据库

CREATE DATABASE [Tom_Hu] ON (NAME = N''Tom_Hu_Data'', FILENAME = N''d:Program FilesMicrosoft SQL ServerMSSQLdataTom_Hu_Data.MDF'' , SIZE = 1, FILEGROWTH = 10%) LOG ON (NAME = N''Tom_Hu_Log'', FILENAME = N''d:Program FilesMicrosoft SQL ServerMSSQLdataTom_Hu_Log.LDF'' , SIZE = 1, FILEGROWTH = 10%)
COLLATE Chinese_PRC_CI_AS
GO

2. --建立一个存储图片的表

CREATE TABLE [Images] (
[id] [int] IDENTITY (1, 1) NOT NULL ,
[ImageName] [varchar] (64) COLLATE Chinese_PRC_CI_AS NOT NULL ,
[Images] [image] NOT NULL ,
[ImageSize] [int] NULL
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO

3.建立一个名为 ImageTest 的asp.net网站

4.在Default.aspx文件中加入以下代码:

<%...@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>关于图片上传和下载的测试</title>
    <link href="css.css" rel="stylesheet" type="text/css" />
</head>
<body style="text-align: left">
    <form id="form1" runat="server">
    <div>
        <table style="border-right: #3333ff thin solid; border-top: #3333ff thin solid; border-left: #3333ff thin solid; border-bottom: #3333ff thin solid;">
            <tr>
                <td colspan="2">
                    <asp:FileUpload ID="UpFileControl" runat="server" /></td>
            </tr>
            <tr>
                <td style="text-align: center">
                    <asp:Button ID="BT_UpFile" runat="server" Text="上传" OnClick="BT_UpFile_Click" /></td>
                <td style="text-align: center">
                    <asp:Button ID="BT_Down" runat="server" Text="下载" OnClick="BT_Down_Click" /></td>
            </tr>
        </table>
    </div>
    </form>
</body>
</html>

5.在配置文件Web.config中写入:

<?xml version="1.0"?>

<configuration>
<appSettings/>
<connectionStrings>
   <add name="databasecon" connectionString="Data Source=.;Initial Catalog=Tom_Hu;Persist Security Info=True;User ID=sa;Password=sa" providerName="System.Data.SqlClient"/>
</connectionStrings>
<system.web>
   
   <compilation debug="true"/>
   
   <authentication mode="Windows"/>
   <!--
            如果在执行请求的过程中出现未处理的错误，
            则通过 <customErrors> 节可以配置相应的处理步骤。具体说来，
            开发人员通过该节可以配置
            要显示的 html 错误页
            以代替错误堆栈跟踪。

6.在Default.aspx.cs文件中写上:

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.IO;

public partial class _Default : System.Web.UI.Page
{
    protected int imageSize;
    protected byte[] imageBody;
    protected string SqlCom = "";
    SqlConnection con = new SqlConnection();
    SqlCommand cmd = new SqlCommand();

    protected void Page_Load(object sender, EventArgs e)
    {
        //创建数据库链接对象
        con = new SqlConnection(ConfigurationManager.ConnectionStrings["databasecon"].ToString());
    }

    //图片上传
    protected void BT_UpFile_Click(object sender, EventArgs e)
    {
        string imagePath;
        string imageType;
        string imageName;
        if (UpFileControl.PostedFile.FileName != "")
        {
            //取得选择的图片路径
            imagePath = UpFileControl.PostedFile.FileName;
            //取得选择的图片扩展名
            imageType = imagePath.Substring(imagePath.LastIndexOf(".") + 1);
            //取得选择的图片名
            imageName = imagePath.Substring(imagePath.LastIndexOf("/") + 1);

            if ("jpg" != imageType && "gif" != imageType)
            {
                Response.Write("对不起!请您选择JPG或者GIF格式的图片!");
                return;
            }
            else
            {
                //建立访问客户端上传文件的对象
                HttpPostedFile SendImage = UpFileControl.PostedFile;
                //取得图片的大小
                imageSize = SendImage.ContentLength;
                imageBody = new Byte[imageSize];
                //建立数据流对象
                Stream StreamObject = SendImage.InputStream;
                //把图像数据放到imageBody中,其中0代表数据指针位置,ImageSize代表要读取的流的长度
                StreamObject.Read(imageBody, 0, imageSize);
                SqlCom = "insert into Images(ImageName,Images,ImageSize,imgtype) VALUES(@ImageName,@Images,@ImageSize,@imgtype) "; // ''" + imageName + "'',''" + imageBody + "'',''" + imageSize.ToString() + "'',''" + imageType + "'')";
                cmd = new SqlCommand(SqlCom,con);
                cmd.Parameters.AddWithValue("@ImageName", imageName);//@Images,@ImageSize,@imgtype
                cmd.Parameters.AddWithValue("@Images", imageBody);
                cmd.Parameters.AddWithValue("@ImageSize", imageSize);
                cmd.Parameters.AddWithValue("@imgtype", imageType);
                con.Open();
                try
                {
                    cmd.ExecuteNonQuery();
                    Response.Write("成功!");
                }
                catch
                {
                    Response.Write("失败!");
                }
                finally
                {
                    con.Close();
                }
            }
        }
    }

    //图片下载
    protected void BT_Down_Click(object sender, EventArgs e)
    {
        SqlCom = "select top 1 * from images order by id desc";
        cmd = new SqlCommand(SqlCom, con);
        con.Open();
        SqlDataReader myreader = cmd.ExecuteReader();
        myreader.Read();
        //设置页面缓冲输出
        Response.Buffer = true;
        //清除缓冲区中的所有内容
        Response.Clear();
        //设置输出流的类型
        Response.ContentType = "gif";
        //为输出流添加HTTP头信息,在这里用图片的名称作为下载的文件名称
        Response.AddHeader("Content-Disposition", "attachment;filename=" +HttpUtility.UrlEncode( myreader["imagename"].ToString(), System.Text.Encoding.GetEncoding("UTF-8")) +";");

        byte[] file = (byte[])myreader["images"];
        //把二进制字符串写入HTTP输出流
        Response.Write(file);
        //向客户端发送所有缓冲的内容
        Response.Flush();
        /**/////将当前所有缓冲的输出发送到客户端,并停止该页的执行
        Response.End();
        con.Close();
        myreader.Close();
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        Image1.ImageUrl = "ShowImg.aspx";
    }
}

asp 的下载见：http://topic.csdn.net/u/20081019/10/5b13c791-772c-4777-8362-ba6a0513537e.html