asp.net保存远程图片的代码

using System; 
using System.Data; 
using System.Configuration; 
using System.Web; 
using System.Web.Security; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
using System.Web.UI.WebControls.WebParts; 
using System.Web.UI.HtmlControls; 
//引入空间 
using System.Net; 
using System.IO; 
using System.Text; 
using System.Text.RegularExpressions; 
using System.Collections; 
/// <summary> 
/// 采集 
/// </summary> 
public class caiji 
{ 
public caiji() 
{ 
// 
// TODO: 在此处添加构造函数逻辑 
// 
} 
/// <summary> 
/// 要采集的网页的连接地址 
/// </summary> 
/// <param name="url">url</param> 
/// <returns></returns> 
public static string caijiByUrl(string url,string chargest,string path) 
{ 
string str = GetSourceTextByUrl(url,chargest); 
ArrayList lib = new ArrayList(); 
int i = 0; 
//根据url取得网站域名 
Uri uri = new Uri(url); 
//Scheme或者协议，一般为http,Host为取得域名 
string baseurl = uri.Scheme + "://" + uri.Host + "/"; 
//提取出url，包括src等信息 
//\S匹配任何非空白字符 
Regex g = new Regex(@"(src=(""|\')\S+\.(gif|jpg|png|bmp)(""|\'))", RegexOptions.Multiline | RegexOptions.IgnoreCase); 
MatchCollection m = g.Matches(str); 
foreach (Match math in m) 
{ 
//已经提取到图片的路径了，但还需要分绝对路径，相对路径，以及后缀名是否为图片，因为可能为.asp,.aspx这些，比如验证码图片 
string imgUrl = math.Groups[0].Value.ToLower();//转成小写,=号之间可能有不定的空格 
//去除src与单引号，双引号 
imgUrl = imgUrl.Replace("src",""); 
imgUrl = imgUrl.Replace("\"",""); 
imgUrl = imgUrl.Replace("'",""); 
imgUrl = imgUrl.Replace("=",""); 
imgUrl = imgUrl.Trim(); 
//路径处理 
if (imgUrl.Substring(0, 4) != "http") 
{ 
//需要判断是否是绝对路径还是相对路径 
if (imgUrl.Substring(0, 1) == "/") 
{ 
imgUrl = baseurl + imgUrl; 
} 
else 
{ 
imgUrl = url.Substring(0,url.LastIndexOf("/") + 1) + imgUrl; 
} 
} 
//判断元素是否已经存在,-1为不存在 
if (lib.IndexOf(imgUrl) == -1) 
{ 
lib.Add(imgUrl); 
} 
} 
string str_ = string.Empty; 
WebClient client = new WebClient(); 
for (int j = 0; j < lib.Count; j++) 
{ 
string savepath = path + DateTime.Now.Month + DateTime.Now.Day + DateTime.Now.Minute + DateTime.Now.Second + j + lib[j].ToString().Substring((lib[j].ToString().Length) -4,4); 
try 
{ 
client.DownloadFile(new Uri(lib[j].ToString()), savepath); 
str_ += lib[j].ToString() + "<br /> 保存路径为：" + savepath + "<br /><br />"; 
} 
catch (Exception e) 
{ 
str_ += e.Message; 
} 
} 
return str_; 
} 
public static string GetSourceTextByUrl(string url,string chargest) 
{ 
WebRequest request = WebRequest.Create(url); 
request.Timeout = 20000;//20秒超时 
WebResponse response = request.GetResponse(); 
Stream resStream = response.GetResponseStream(); 
StreamReader sr = new StreamReader(resStream,Encoding.GetEncoding(chargest)); 
return sr.ReadToEnd(); 
} 
} 
 
使用：比如我是保存到upload文件夹中的： 
 代码如下:

string path = Server.MapPath("~/upload/"); 
Response.Write(caiji.caijiByUrl(//www.gxlcms.com, "utf-8", path));