本文實例為大家分享了基于C#實現網頁爬蟲的詳細代碼，供大家參考，具體內容如下
HTTP請求工具類：
功能：
1、獲取網頁html
2、下載網絡圖片
using System;using System.Collections.Generic;using System.IO;using System.Linq;using System.Net;using System.Text;using System.Threading.Tasks;using System.Windows.Forms;namespace Utils{ /// <summary> /// HTTP請求工具類 /// </summary> public class HttpRequestUtil { /// <summary> /// 獲取頁面html /// </summary> public static string GetPageHtml(string url) { // 設置參數 HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest; request.UserAgent = "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0)"; //發送請求并獲取相應回應數據 HttpWebResponse response = request.GetResponse() as HttpWebResponse; //直到request.GetResponse()程序才開始向目標網頁發送Post請求 Stream responseStream = response.GetResponseStream(); StreamReader sr = new StreamReader(responseStream, Encoding.UTF8); //返回結果網頁（html）代碼 string content = sr.ReadToEnd(); return content; } /// <summary> /// Http下載文件 /// </summary> public static void HttpDownloadFile(string url) { int pos = url.LastIndexOf("/") + 1; string fileName = url.Substring(pos); string path = Application.StartupPath + "//download"; if (!Directory.Exists(path)) { Directory.CreateDirectory(path); } string filePathName = path + "//" + fileName; if (File.Exists(filePathName)) return; // 設置參數 HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest; request.UserAgent = "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0)"; request.Proxy = null; //發送請求并獲取相應回應數據 HttpWebResponse response = request.GetResponse() as HttpWebResponse; //直到request.GetResponse()程序才開始向目標網頁發送Post請求 Stream responseStream = response.GetResponseStream(); //創建本地文件寫入流 Stream stream = new FileStream(filePathName, FileMode.Create); byte[] bArr = new byte[1024]; int size = responseStream.Read(bArr, 0, (int)bArr.Length); while (size > 0) { stream.Write(bArr, 0, size); size = responseStream.Read(bArr, 0, (int)bArr.Length); } stream.Close(); responseStream.Close(); } }} 多線程爬取網頁代碼：
using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.IO;using System.Linq;using System.Text;using System.Text.RegularExpressions;using System.Threading;using System.Threading.Tasks;using System.Windows.Forms;using Utils;namespace 爬蟲{ public partial class Form1 : Form { List<Thread> threadList = new List<Thread>(); Thread thread = null; public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { DateTime dtStart = DateTime.Now; button3.Enabled = true; button2.Enabled = true; button1.Enabled = false; int page = 0; int count = 0; int personCount = 0; lblPage.Text = "已完成頁數：0"; int index = 0; for (int i = 1; i <= 10; i++) { thread = new Thread(new ParameterizedThreadStart(delegate(object obj) { for (int j = 1; j <= 10; j++) { try { index = (Convert.ToInt32(obj) - 1) * 10 + j; string pageHtml = HttpRequestUtil.GetPageHtml("http://tt.mop.com/c44/0/1_" + index.ToString() + ".html"); Regex regA = new Regex("<a[//s]+class=/"J-userPic([^<>]*?)[//s]+href=/"([^/"]*?)/""); Regex regImg = new Regex("<p class=/"tc mb10/"><img[//s]+src=/"([^/"]*?)/""); MatchCollection mc = regA.Matches(pageHtml); foreach (Match match in mc) { int start = match.ToString().IndexOf("href=/""); string url = match.ToString().Substring(start + 6); int end = url.IndexOf("/""); url = url.Substring(0, end); if (url.IndexOf("/") == 0) { string imgPageHtml = HttpRequestUtil.GetPageHtml("http://tt.mop.com" + url); personCount++; lblPerson.Invoke(new Action(delegate() { lblPerson.Text = "已完成條數：" + personCount.ToString(); })); MatchCollection mcImgPage = regImg.Matches(imgPageHtml); foreach (Match matchImgPage in mcImgPage) { start = matchImgPage.ToString().IndexOf("src=/""); string imgUrl = matchImgPage.ToString().Substring(start + 5); end = imgUrl.IndexOf("/""); imgUrl = imgUrl.Substring(0, end); if (imgUrl.IndexOf("http://i1") == 0) { try { HttpRequestUtil.HttpDownloadFile(imgUrl); count++; lblNum.Invoke(new Action(delegate() { lblNum.Text = "已下載圖片數" + count.ToString(); DateTime dt = DateTime.Now; double time = dt.Subtract(dtStart).TotalSeconds; if (time > 0) { lblSpeed.Text = "速度：" + (count / time).ToString("0.0") + "張/秒"; } })); } catch { } Thread.Sleep(1); } } } } } catch { } page++; lblPage.Invoke(new Action(delegate() { lblPage.Text = "已完成頁數：" + page.ToString(); })); if (page == 100) { button1.Invoke(new Action(delegate() { button1.Enabled = true; })); MessageBox.Show("完成！"); } } })); thread.Start(i); threadList.Add(thread); } } private void button2_Click(object sender, EventArgs e) { button1.Invoke(new Action(delegate() { foreach (Thread thread in threadList) { if (thread.ThreadState == ThreadState.Suspended) { thread.Resume(); } thread.Abort(); } button1.Enabled = true; button2.Enabled = false; button3.Enabled = false; button4.Enabled = false; })); } private void Form1_FormClosing(object sender, FormClosingEventArgs e) { foreach (Thread thread in threadList) { thread.Abort(); } } private void button3_Click(object sender, EventArgs e) { foreach (Thread thread in threadList) { if (thread.ThreadState == ThreadState.Running) { thread.Suspend(); } } button3.Enabled = false; button4.Enabled = true; } private void button4_Click(object sender, EventArgs e) { foreach (Thread thread in threadList) { if (thread.ThreadState == ThreadState.Suspended) { thread.Resume(); } } button3.Enabled = true; button4.Enabled = false; } }} 截圖：
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