C#多线程爬虫抓取免费代理IP

   这里用到一个HTML解析辅助类：HtmlAgilityPack,如果没有网上找一个增加到库里，这个插件有很多版本,如果你开发环境是使用VS2005就2.0的类库，VS2010就使用4.0,以此类推..........然后直接创建一个控制台应用，将我下面的代码COPY替换就可以运行,下面就来讲讲我两年前做爬虫经历，当时是给一家公司做，也是用的C#，不过当时遇到一个头痛的问题就是抓的图片有病毒，然后系统挂了几次。所以抓网站图片要注意安全，虽然我这里没涉及到图片，但是还是提醒下看文章的朋友。

 class Program
    {
//存放所有抓取的代理
public static List<proxy> masterPorxyList = new List<proxy>();
//代理IP类
public class proxy
        {
public string ip;

public string port;
public int  speed;

public proxy(string pip,string pport,int pspeed)

            {
this.ip = pip;
this.port = pport;
this.speed = pspeed;
             }


        }
       //抓去处理方法
static void getProxyList(object pageIndex)
        {

string urlCombin = "http://www.xicidaili.com/wt/" + pageIndex.ToString();
string catchHtml = catchProxIpMethord(urlCombin, "UTF8");


            HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
           doc.LoadHtml(catchHtml);


           HtmlNode table = doc.DocumentNode.SelectSingleNode("//div[@id='wrapper']//div[@id='body']/table[1]");

           HtmlNodeCollection collectiontrs = table.SelectNodes("./tr");   



for (int i = 0; i < collectiontrs.Count; i++)
               {
                   HtmlAgilityPack.HtmlNode itemtr = collectiontrs[i];


                   HtmlNodeCollection collectiontds = itemtr.ChildNodes;
//table中第一个是能用的代理标题，所以这里从第二行TR开始取值
if (i>0)
                   {
                       HtmlNode itemtdip = (HtmlNode)collectiontds[3];

                       HtmlNode itemtdport = (HtmlNode)collectiontds[5];

                       HtmlNode itemtdspeed = (HtmlNode)collectiontds[13];

string ip = itemtdip.InnerText.Trim();
string port = itemtdport.InnerText.Trim();


string speed = itemtdspeed.InnerHtml;
int beginIndex = speed.IndexOf(":", 0, speed.Length);
int endIndex = speed.IndexOf("%", 0, speed.Length);

int subSpeed = int.Parse(speed.Substring(beginIndex + 1, endIndex - beginIndex - 1));
//如果速度展示条的值大于90,表示这个代理速度快。
if (subSpeed > 90)
                        {
                            proxy temp = new proxy(ip, port, subSpeed);

                            masterPorxyList.Add(temp);
                            Console.WriteLine("当前是第:" + masterPorxyList.Count.ToString() + "个代理IP");
                       }

                      }


               }

        }

//抓网页方法
static string catchProxIpMethord(string url,string encoding )
        {

string htmlStr = "";
try
            {
if (!String.IsNullOrEmpty(url))
                {
                    WebRequest request = WebRequest.Create(url);    
                    WebResponse response = request.GetResponse();           
                    Stream datastream = response.GetResponseStream(); 
                    Encoding ec = Encoding.Default;
if (encoding == "UTF8")
                    {
                        ec = Encoding.UTF8;
                    }
else if (encoding == "Default")
                    {
                        ec = Encoding.Default;
                    }
                    StreamReader reader = new StreamReader(datastream, ec);
                    htmlStr = reader.ReadToEnd();               
                    reader.Close();
                    datastream.Close();
                    response.Close();
                }
            }
catch { }
return htmlStr;
        }


static void Main(string[] args)
         {
//多线程同时抓15页
for (int i = 1; i <= 15; i++)
             {


                 ThreadPool.QueueUserWorkItem(getProxyList, i);
             }
             Console.Read();
         }

    }