asp.net继承IHttpHandler接口实现给网站图片添加水印功能实例

public class ImageSY : IHttpHandler{  public ImageSY()  {    //    //TODO: 在此处添加构造函数逻辑    //  }  #region IHttpHandler 成员  public bool IsReusable  {    get { return true; }  }  public void ProcessRequest(HttpContext context)  {    //获得请求的物理图片路径    string imagePath = context.Request.PhysicalPath;    System.Drawing.Image image = null;    if (File.Exists(imagePath))    {      //定义水印文字      string text = "本图片来至我的网站";      //定义水印文字字体大小      int fontSize = 22;      //水印文字字体      Font font = new Font("宋体", fontSize);      //根据图片物理地址加载图片      image = System.Drawing.Image.FromFile(imagePath);      Graphics g = Graphics.FromImage(image);      //获取要绘制水印文字所需要的显示区域大小      SizeF size = g.MeasureString(text, font);      if (size.Width > image.Width || size.Height > image.Height)      {      }      else      {        Brush brush = Brushes.Red;        g.DrawString(text, font, brush, image.Width - size.Width, image.Height - size.Height);        g.Dispose();      }    }    else    {    }    image.Save(context.Response.OutputStream, ImageFormat.Jpeg);  }  #endregion}

<location path="images"> <system.web>  <httpHandlers>  <!---对jpg文件添加水印-->  <add verb="*" type="ImageSY" path="*.jpg"/>  <add verb="*" type="ImageSY" path="*.gif"/>  <add verb="*" type="ImageSY" path="*.bmp"/>  </httpHandlers> </system.web> </location>