文件的上传下载

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使用FileUpload控件上传图片并自动生成缩略图、带文字和图片的水印图

public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void Button1_Click(object sender, EventArgs e) { if (FileUpload1.HasFile) { string fileContentType = FileUpload1.PostedFile.ContentType; if (fileContentType == "image/bmp" || fileContentType == "image/gif" || fileContentType == "image/pjpeg") { string name = FileUpload1.PostedFile.FileName; // 客户端文件路径 FileInfo file = new FileInfo(name); string fileName = file.Name; // 文件名称 string fileName_s = "s_" + file.Name; // 缩略图文件名称 string fileName_sy = "sy_" + file.Name; // 水印图文件名称（文字） string fileName_syp = "syp_" + file.Name; // 水印图文件名称（图片） string webFilePath = Server.MapPath("file/" + fileName); // 服务器端文件路径 string webFilePath_s = Server.MapPath("file/" + fileName_s);　　// 服务器端缩略图路径 string webFilePath_sy = Server.MapPath("file/" + fileName_sy);　// 服务器端带水印图路径(文字) string webFilePath_syp = Server.MapPath("file/" + fileName_syp);　// 服务器端带水印图路径(图片) string webFilePath_sypf = Server.MapPath("file/shuiyin.jpg");　// 服务器端水印图路径(图片) if (!File.Exists(webFilePath)) { try { FileUpload1.SaveAs(webFilePath); // 使用 SaveAs 方法保存文件 AddShuiYinWord(webFilePath, webFilePath_sy); AddShuiYinPic(webFilePath, webFilePath_syp, webFilePath_sypf); MakeThumbnail(webFilePath, webFilePath_s, 130, 130, "Cut"); // 生成缩略图方法 Label1.Text = "提示：文件“" + fileName + "”成功上传，并生成“" + fileName_s + "”缩略图，文件类型为：" + FileUpload1.PostedFile.ContentType + "，文件大小为：" + FileUpload1.PostedFile.ContentLength + "B"; } catch (Exception ex) { Label1.Text = "提示：文件上传失败，失败原因：" + ex.Message; } } else { Label1.Text = "提示：文件已经存在，请重命名后上传"; } } else { Label1.Text = "提示：文件类型不符"; } } } /// 
 /// 生成缩略图 ///  /// 源图路径（物理路径） /// 缩略图路径（物理路径） /// 缩略图宽度 /// 缩略图高度 /// 生成缩略图的方式 public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode) { System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath); int towidth = width; int toheight = height; int x = 0; int y = 0; int ow = originalImage.Width; int oh = originalImage.Height; switch (mode) { case "HW"://指定高宽缩放（可能变形） break; case "W"://指定宽，高按比例 toheight = originalImage.Height * width / originalImage.Width; break; case "H"://指定高，宽按比例 towidth = originalImage.Width * height / originalImage.Height; break; case "Cut"://指定高宽裁减（不变形） if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight) { oh = originalImage.Height; ow = originalImage.Height * towidth / toheight; y = 0; x = (originalImage.Width - ow) / 2; } else { ow = originalImage.Width; oh = originalImage.Width * height / towidth; x = 0; y = (originalImage.Height - oh) / 2; } break; default: break; } //新建一个bmp图片 System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight); //新建一个画板 System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap); //设置高质量插值法 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; //设置高质量,低速度呈现平滑程度 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; //清空画布并以透明背景色填充 g.Clear(System.Drawing.Color.Transparent); //在指定位置并且按指定大小绘制原图片的指定部分 g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight), new System.Drawing.Rectangle(x, y, ow, oh), System.Drawing.GraphicsUnit.Pixel); try { //以jpg格式保存缩略图 bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg); } catch (System.Exception e) { throw e; } finally { originalImage.Dispose(); bitmap.Dispose(); g.Dispose(); } } /// 
 /// 在图片上增加文字水印 ///  /// 原服务器图片路径 /// 生成的带文字水印的图片路径 protected void AddShuiYinWord(string Path, string Path_sy) { string addText = "测试水印"; System.Drawing.Image image = System.Drawing.Image.FromFile(Path); System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image); g.DrawImage(image, 0, 0, image.Width, image.Height); System.Drawing.Font f = new System.Drawing.Font("Verdana", 16); System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.Blue); g.DrawString(addText, f, b, 15, 15); g.Dispose(); image.Save(Path_sy); image.Dispose(); } /// 
 /// 在图片上生成图片水印 ///  /// 原服务器图片路径 /// 生成的带图片水印的图片路径 /// 水印图片路径 protected void AddShuiYinPic(string Path, string Path_syp, string Path_sypf) { System.Drawing.Image image = System.Drawing.Image.FromFile(Path); System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf); System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image); g.DrawImage(copyImage, new System.Drawing.Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, System.Drawing.GraphicsUnit.Pixel); g.Dispose(); image.Save(Path_syp); image.Dispose(); } }

ASP.NET 文件下载 //TransmitFile实现下载 
    protected void Button1_Click(object sender, EventArgs e)
    {
        /* 
        微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite 
        下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。 
        代码如下： 
        */         Response.ContentType = "application/x-zip-compressed";
        Response.AddHeader("Content-Disposition", "attachment;filename=z.zip");
        string filename = Server.MapPath("DownLoad/z.zip");
        Response.TransmitFile(filename);
    }
    //WriteFile实现下载 
    protected void Button2_Click(object sender, EventArgs e)
    {
        /* 
        using System.IO;
        */
        string fileName = "asd.txt";//客户端保存的文件名 
        string filePath = Server.MapPath("DownLoad/aaa.txt");//路径
        FileInfo fileInfo = new FileInfo(filePath);
        Response.Clear();
        Response.ClearContent();
        Response.ClearHeaders();
        Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
        Response.AddHeader("Content-Length", fileInfo.Length.ToString());
        Response.AddHeader("Content-Transfer-Encoding", "binary");
        Response.ContentType = "application/octet-stream";
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
        Response.WriteFile(fileInfo.FullName);
        Response.Flush();
        Response.End();
    }
    //WriteFile分块下载 
    protected void Button3_Click(object sender, EventArgs e)
    {
        string fileName = "aaa.txt";//客户端保存的文件名 
        string filePath = Server.MapPath("DownLoad/aaa.txt");//路径
        System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);
        if (fileInfo.Exists == true)
        {
            const long ChunkSize = 102400;//100K 每次读取文件，只读取100K，这样可以缓解服务器的压力 
            byte[] buffer = new byte[ChunkSize];
            Response.Clear();
            System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);
            long dataLengthToRead = iStream.Length;//获取下载的文件总大小 
            Response.ContentType = "application/octet-stream";
            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));
            while (dataLengthToRead > 0 && Response.IsClientConnected)
            {
                int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小 
                Response.OutputStream.Write(buffer, 0, lengthRead);
                Response.Flush();
                dataLengthToRead = dataLengthToRead - lengthRead;
            }
            Response.Close();
        }
    }
    //流方式下载 
    protected void Button4_Click(object sender, EventArgs e)
    {
        string fileName = "aaa.txt";//客户端保存的文件名 
        string filePath = Server.MapPath("DownLoad/aaa.txt");//路径
        //以字符流的形式下载文件 
        FileStream fs = new FileStream(filePath, FileMode.Open);
        byte[] bytes = new byte[(int)fs.Length];
        fs.Read(bytes, 0, bytes.Length);
        fs.Close();
        Response.ContentType = "application/octet-stream";
        //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));
        Response.BinaryWrite(bytes);
        Response.Flush();
        Response.End();
    }
 
//----------------------------------------------------------
 
 
public void DownloadFile( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FileBody )
{
　　WebForm.Response.ClearHeaders();
　　WebForm.Response.Clear();
　　WebForm.Response.Expires = 0;
　　WebForm.Response.Buffer = true;
　　WebForm.Response.AddHeader("Accept-Language", "zh-tw");
　　//'文件名称
　　WebForm.Response.AddHeader("content-disposition", "attachment; filename='"+System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8)+"'");
　　WebForm.Response.ContentType = "Application/octet-stream";
　　//'文件内容
　　WebForm.Response.Write(FileBody);//-----------
    WebForm.Response.End();
}

//上面这段代码是下载一个动态产生的文本文件，若这个文件已经存在于服务器端的实体路径，则可以通过下面的函数：
public void DownloadFileByFilePath( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FilePath )
{
　　WebForm.Response.ClearHeaders();
　　WebForm.Response.Clear();
　　WebForm.Response.Expires = 0;
    WebForm.Response.Buffer = true;
　　WebForm.Response.AddHeader("Accept-Language", "zh-tw");
　　//文件名称
　　WebForm.Response.AddHeader("content-disposition", "attachment; filename='" + System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8) +"'" );
　　WebForm.Response.ContentType = "Application/octet-stream";
　　//文件内容
　　WebForm.Response.Write(System.IO.File.ReadAllBytes(FilePath));//---------
　　WebForm.Response.End();