asp.net mvc实现图片下载防盗链及提示是否存在!

首先声明此方法对服务器影响很大：
目的:用file/图片名称代替files/图片名称访问，自定义无图片提示和防盗链

在gobal.ascx中添加规则:

routes.MapRoute(
                "Image",
                "file/{fileName}",
                new { controller = "file", action = "producePics" },
                new { fileName = @"^(\w+).(\w+)$" }
                );

创建images文件夹新建两张图片.nopic.png和notallowlink.png
把图片文件放在Files文件夹下(该例子中放了6张图片)，等下我们用file/图片名称代替files/图片名称访问

创建File controller并创建Index action

        public ActionResult Index()
        {
            DirectoryInfo dir = new DirectoryInfo(Server.MapPath("~/files/"));
            FileInfo[] files=dir.GetFiles();

            ViewData["dirinfo"]="该文件夹下共有"+files.Length+"个文件";
            foreach (FileInfo file in files)
            {
                ViewData["imagelist"] += "<li><a href=\"/file/" + file.Name+ "\"><img src=\"" +
                    "/file/" + file.Name + "\"/></a></li>";
            }
            return View();
        }

创建 Index view

Code

扩展FileController

using System.IO;

    public class FileController : Controller
    {
        public FileResult ProducePic(string fileName)
        {
            //00:00:00.0039062  最差的
             /*
         FileStream fs=new FileStream(Server.MapPath("~/files/"+fileName),FileMode.Open,FileAccess.Read);
             byte[] buffer=new byte[fs.Length];
             fs.Read(buffer, 0, buffer.Length);
             fs.Flush();
             fs.Close();
             return File(buffer, "Image/JPEG");*/

            //00:00:00.0029297 (刷新几次发现偶尔为00:00:00.00009611)
            //FileStream fs = new FileStream(Server.MapPath("~/files/" + fileName),FileMode.Open,FileAccess.Read);
            //return File(fs, "Image/JPEG");

            //00:00:00.0029296 处理最快的方法 (多刷新几次发现基本为00:00:00.00000011)
            //return File(Server.MapPath("~/files/") + fileName, "Image/JPEG");

            //如果不存在图片则显示无图提示的图片
            /*
            FileInfo file = new FileInfo(Server.MapPath("~/files/") + fileName);
            if (!file.Exists) file = new FileInfo(Server.MapPath("~/files/") + "nopic.jpg");
            FileStream fs = new FileStream(file.FullName, FileMode.Open, FileAccess.Read);
            FileResult files = File(fs, "Image/JPEG");
            fs.Flush();
            return files; */

            string filePath = null;
            bool isAllowLink=Request.Url.Host == "localhost";               //是否允许外部链接
            if (!isAllowLink)
            {
                filePath = Server.MapPath("~/images/") + "notallowlink.png";
            }
            else
            {
                filePath = Server.MapPath("~/files/") + fileName;           //获取图片地址
                if (!System.IO.File.Exists(filePath))                       //图片不存在的话显示提示的图片
                    filePath = Server.MapPath("~/images/" + "nopic.png");
            }
            return File(filePath, "Image/GIF");
        }
    }

实现结果如下:

http://www.cnyolee.com