模版和处理程序
封面数字水印：运用httphandler技术
封面数字水印的实现：
1.创建一个Ihttphandler的类Handler1
2.在Handler1中写代码
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Drawing;
namespace WebApplication1
{
/// <summary>
/// Handler1 的摘要说明
/// </summary>
public class Handler1 : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
//
string path = "~/ProductImgs/";
string a = context.Request.MapPath(path + context.Request.Params["id"].ToString() + ".jpg");
Image m = null;
if (File.Exists(a) )
{
m = Image.FromFile(a);
Graphics g = Graphics.FromImage(m);
g.DrawString("12345", new Font("宋体", 20), Brushes.Red, m.Width - 60, m.Height - 20);
g.Dispose();
}
else
{
m = Image.FromFile(context .Request.MapPath (path ));
}
context.Response.ContentType = "image/jpeg";
m.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
m.Dispose();
context.Response.End();
}
public bool IsReusable
{
get
{
return false;
}
}
}
}
3.修改Default.aspx中图片的src属性
<body>
<form id="form1" runat="server">
<div>
<img alt="" class="style1" src="Handler1.ashx?id=1" />
<img alt="" class="style2" src="Handler1.ashx?id=2" />
<img alt="" class="style1" src="Handler1.ashx?id=3" />
<img alt="" class="style2" src="Handler1.ashx?id=4" />
</div>
</form>
</body>
运行结果如下：
数字水印的实现（全局方式）
1.修改web.config文件，在文件中添加以下代码行
<httpHandlers> <addverb="* "path="ProductImgs/*.jpg" validate="false" type="WebApplication1.Handler1"/> </httpHandlers>
Path:访问路径
Type：指定的处理程序
2.创建一个Ihttphandler的类Handler1
3. Handler1代码
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Drawing;
namespace WebApplication1
{
///<summary>
/// Handler1 的摘要说明
///</summary>
public class Handler1 : IHttpHandler
{
public void ProcessRequest(HttpContextcontext)
{
//指定文件夹
stringOL = "~/ProductImgs/default.jpg";
//定义一个图片
Imageimage = null;
//判断地址是否存在
if (File.Exists (context.Request.PhysicalPath ))
{
//加载文件
image = Image.FromFile(context.Request.PhysicalPath);
//实例化画布
Graphicsg = Graphics.FromImage(image );
//在image上会在水印
g.DrawString("hahahhahha", newFont("",20), Brushes.Red, image.Width-120,image.Height-25);
//释放画布
g.Dispose();
}
else
{
image = Image.FromFile(context .Request.MapPath(OL));
}
//设置输出类型为jpeg图片
context.Response.ContentType = "image.jpeg";
//将修改的图片存入文件流
image.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
image.Dispose();
context.Response.End();
}
public bool IsReusable
{
get
{
returnfalse;
}
}
}
}