我的图书封面水印为什么实现不了呢？

Question

看你的逻辑是不是：原始图片cover 需要转换成水印图片 water 
可你最后输出和保存，就和water 没扯上关系context.Response.ContentType = "image/jpeg";
//将修改的图片存入输出流
cover.Save(context.Response.OutputStream, ImageFormat.Jpeg);
cover.Dispose();//释放你看下是不是逻辑问题

Answer 1

<add verb="*" path="~/Admin/BookCovers/*.jpg" type="CoverHandler" />
这个不要用虚拟路径，
改成
<add verb="*" path="Admin/BookCovers/*.jpg" type="CoverHandler" />
这个试试。

Answer 2

配置文件路径是否引用正确
iis是否有添加相应映射
        public void ProcessRequest(HttpContext context)
        {
            string path = context.Request.PhysicalPath;
            string water = context.Server.MapPath("/water/water.png");
            if (!File.Exists(path))
            {
                context.Response.WriteFile(context.Server.MapPath("/error/error.gif"));
                context.Response.End();
            }
            System.Drawing.Image waterImage = System.Drawing.Image.FromFile(water);
            System.Drawing.Image Image = System.Drawing.Image.FromFile(path);
            if (Image.PixelFormat == PixelFormat.Format1bppIndexed || Image.PixelFormat == PixelFormat.Format4bppIndexed || Image.PixelFormat == PixelFormat.Format8bppIndexed)
            {
                Bitmap bitmap = new Bitmap(Image.Width, Image.Height);
                Graphics gtemp = Graphics.FromImage(bitmap);
                gtemp.DrawImage(Image, 0, 0, bitmap.Width, bitmap.Height);
                gtemp.DrawImage(waterImage, new Rectangle(Image.Width - waterImage.Width, Image.Height - waterImage.Height, waterImage.Width, waterImage.Height), new Rectangle(0, 0, waterImage.Width, waterImage.Height), GraphicsUnit.Pixel);
                bitmap.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
                bitmap.Dispose();
                gtemp.Dispose();
            }
            else
            {
                Graphics g = Graphics.FromImage(Image);
                g.DrawImage(waterImage, new Rectangle(Image.Width - waterImage.Width, Image.Height - waterImage.Height, waterImage.Width, waterImage.Height), new Rectangle(0, 0, waterImage.Width, waterImage.Height), GraphicsUnit.Pixel);
                Image.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
                g.Dispose();
            }
            waterImage.Dispose();
            Image.Dispose();
            context.Response.ContentType = "image/jpeg";
            context.Response.End();
        }
<add verb="*" path="images/*.jpg,images/*.gif" type="HandlerClass.water,HandlerClass"/>

Answer 3

再次我说声谢谢了！ 我都试过你们所说的办法  还是不能实现效果。  
<add verb="*" path="~/Admin/BookCovers/*.jpg" type="CoverHandler" />
改成
<add verb="*" path="Admin/BookCovers/*.jpg" type="CoverHandler" />
结果不显示图片。
我没启用IIS，不过我照着写了一遍也是不好用。