封装一个 HttpWebRequest 和 HttpWebResponse 常用的操作类

直接贴代码了：

解决方案截图：

HttpClientHelper.cs

using System;
using System.Text;
using System.Net;
using System.IO;
using System.Globalization;
using System.Collections.Specialized;
using System.Web;

namespace DearBruce.WebRequestDemo.CoreLib
{
    /// <summary>
    /// WebClient 帮助器
    /// </summary>
    public class HttpClientHelper
    {
        /// <summary>
        /// 创建默认的 
        /// </summary>
        /// <param name="url">请求的地址</param>
        /// <returns></returns>
        public static HttpWebRequest CreateHttpWebRequest(string url)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.UserAgent = FakeUserAgentRepository.InternetExplorer8.UserAgent;
            request.AllowAutoRedirect = true;
            //request.Method = "GET";
            request.KeepAlive = true;
            request.Referer = null;
            request.Timeout = 100000; // 默认 100 秒
            request.Headers["Accept-Language"] = CultureInfo.CreateSpecificCulture("zh-CN").Name;

            return request;
        }

        /// <summary>
        /// 向 HttpWebRequest 请求流写入 POST 数据
        /// </summary>
        /// <param name="request">HttpWebRequest 对象</param>
        /// <param name="postVariables">提交的数据。比如：UserName=bruce&Password=123456 。</param>
        /// <param name="encoding">数据编码，可为 null。如果为 null ，则默认 UTF8 编码 </param>
        public static void WritePostData(HttpWebRequest request, NameValueCollection postVariables, Encoding encoding)
        {
            string postData = GetHttpPostVars(postVariables);
            WritePostData(request, postData, encoding);
        }

        /// <summary>
        /// 向 HttpWebRequest 请求流写入 POST 数据
        /// </summary>
        /// <param name="request">HttpWebRequest 对象</param>
        /// <param name="postData">提交的数据。比如：UserName=bruce&Password=123456 。注意：如果 IsNullOrEmpty 则不会向 HttpWebRequest 请求流中写入数据</param>
        /// <param name="encoding">数据编码，可为 null。如果为 null ，则默认 UTF8 编码 </param>
        public static void WritePostData(HttpWebRequest request, string postData, Encoding encoding)
        {
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }
            if (string.IsNullOrEmpty(postData))
            {
                return;
            }
            if (encoding == null)
            {
                encoding = Encoding.UTF8;
            }
            if (request.Method != "POST")
            {
                request.Method = "POST";
                request.ContentType = "application/x-www-form-urlencoded; charset=" + encoding.WebName;
            }
            using (BinaryWriter bw = new BinaryWriter(request.GetRequestStream()))
            {
                bw.Write(encoding.GetBytes(postData));
                bw.Flush();
            }
        }

        /// <summary>
        /// 从 NameValueCollection 中得到 PostData
        /// </summary>
        /// <param name="variables">集合</param>
        /// <returns>PostData</returns>
        public static string GetHttpPostVars(NameValueCollection variables)
        {
            StringBuilder builder = new StringBuilder();
            for (int i = 0; i < variables.Count; i++)
            {
                string key = variables.GetKey(i);
                string[] values = variables.GetValues(i);
                if (values != null)
                {
                    foreach (string value in values)
                    {
                        builder.AppendFormat("{0}={1}", HttpUtility.UrlEncode(key), HttpUtility.UrlEncode(value));
                    }
                }
                if (i < variables.Count - 1)
                {
                    builder.Append("&");
                }
            }
            return builder.ToString();
        }

        /// <summary>
        /// 根据 HttpWebRequest 请求对象得到响应的 Html 代码
        /// </summary>
        /// <param name="request">HttpWebRequest 对象</param>
        /// <returns></returns>
        public static string GetResponseText(HttpWebRequest request)
        {
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }
            HttpWebResponse response = null;

            try
            {
                response = (HttpWebResponse)request.GetResponse();
            }
            catch (WebException wex)
            {
                if (wex.Response == null)
                {
                    return wex.Message;
                }
                response = (HttpWebResponse)wex.Response;
            }
            using (response)
            {
                Stream strem = response.GetResponseStream();
                using (StreamReader reader = new StreamReader(strem, Encoding.GetEncoding(response.CharacterSet)))
                {
                    return reader.ReadToEnd();
                }
            }
        }

        /// <summary>
        /// 发送 Get 请求，得到 Html 代码
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="cookieContainer">Cookie 容器，可为 null。响应时远程服务器返回的 Cookie 也自动包含其中</param>
        /// <returns>Html 代码</returns>
        public static string SendHttpGet(string url, CookieContainer cookieContainer)
        {
            HttpWebRequest request = CreateHttpWebRequest(url);

            if (cookieContainer != null)
            {
                request.CookieContainer = cookieContainer;
            }
            return GetResponseText(request);
        }

        /// <summary>
        /// 发送 POST 请求，得到 Html 代码
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="postData">提交的数据。</param>
        /// <param name="cookieContainer">Cookie 容器，可为 null。响应时远程服务器返回的 Cookie 也自动包含其中</param>
        /// <returns>Html 代码</returns>
        public static string SendHttpPost(string url, string postData, CookieContainer cookieContainer)
        {
            HttpWebRequest request = CreateHttpWebRequest(url);

            if (cookieContainer != null)
            {
                request.CookieContainer = cookieContainer;
            }
            WritePostData(request, postData, Encoding.UTF8);

            return GetResponseText(request);
        }

        /// <summary>
        /// 发送 POST 请求，得到 Html 代码
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="postVariables">提交的数据。</param>
        /// <param name="cookieContainer">Cookie 容器，可为 null。响应时远程服务器返回的 Cookie 也自动包含其中</param>
        /// <returns>Html 代码</returns>
        public static string SendHttpPost(string url, NameValueCollection postVariables, CookieContainer cookieContainer)
        {
            string postData = GetHttpPostVars(postVariables);
            return SendHttpPost(url, postData, cookieContainer);
        }
    }
}

 

FakeUserAgentRepository.cs

    public class FakeUserAgentRepository
    {
        // Fields
        public static readonly FakeUserAgent Chrome = 
            new FakeUserAgent("Chrome", "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.13 (KHTML, like Gecko) Chrome/9.0.597.98 Safari/534.13");
        public static readonly FakeUserAgent Firefox11 = new 
            FakeUserAgent("Firefox", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:11.0) Gecko/20100101 Firefox/11.0");
        public static readonly FakeUserAgent InternetExplorer8 = 
            new FakeUserAgent("Internet Explorer 8", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; )");
    }

 

TestHttpClientHelper.aspx.cs

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using DearBruce.WebRequestDemo.CoreLib;
using System.Net;
using System.IO;

namespace DearBruce.WebRequestDemo.WebFormUI
{
    public partial class TestHttpClientHelper : System.Web.UI.Page
    {

        private static readonly string LoginUrl = "http://passport.cnblogs.com/login.aspx?ReturnUrl=http://www.cnblogs.com/";
        private static readonly string CategoryListUrl = "http://www.cnblogs.com/";

        protected void Page_Load(object sender, EventArgs e)
        {
            
        }

        protected override void OnPreRender(EventArgs e)
        {
            TestLogin();
            DownloadFile();
            base.OnPreRender(e);
        }

        private void TestLogin()
        {
            // 创建一个CookieContainer实例，供多次请求之间共享Cookie
            CookieContainer cookieContainer = new CookieContainer();

            // 首先去登录页面登录
            //string responseHtml = HttpClientHelper.SendHttpPost(LoginUrl, "tbUserName=bruce&tbPassword=123456", cookieContainer);
            // 或者向下面这样调用
            NameValueCollection postDataCollection = new NameValueCollection()
            {
                { "tbUserName", "bruce" },
                { "tbPassword", "123456" }
            };
            string responseHtml = HttpClientHelper.SendHttpPost(LoginUrl, postDataCollection, cookieContainer);

            // 如果登录成功 responseHtml 是新闻列表页面的 源代码
            // 此时cookieContainer已经包含了服务端生成的登录Cookie
            TestNewsList(cookieContainer);

        }

        private void TestNewsList(CookieContainer cookieContainer)
        {
            // 再去访问要请求的页面。
            string html = HttpClientHelper.SendHttpGet(CategoryListUrl, cookieContainer);

            if (html.IndexOf("博客园") > 0)
                Response.Write("调用成功。");
            else
                Response.Write("页面结果不符合预期。");

            // 如果还要访问其它的受限页面，可以继续调用。
        }



        private void DownloadFile()
        {
            string requstImgUrl = "http://pic002.cnblogs.com/images/2012/148372/2012061410561396.png";
            string imgName = Path.GetFileName(requstImgUrl);

            string imgFileName = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, Guid.NewGuid() + ".jpg");
            WebClient webClient = new WebClient();

            webClient.Headers.Set("Referer", "http://www.baidu.com");
            webClient.Headers.Set("User-Agent", FakeUserAgentRepository.InternetExplorer8.UserAgent);

            webClient.DownloadFileAsync(new Uri(requstImgUrl), imgFileName, imgName);
            webClient.DownloadFileCompleted += new System.ComponentModel.AsyncCompletedEventHandler(webClient_DownloadFileCompleted);

            System.Threading.Thread.Sleep(3000);
        }


        static void webClient_DownloadFileCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
        {
            WebClient webClient = (WebClient)sender;
            if (e.Error != null)
            {
                string imgName = (string)e.UserState;
                Console.WriteLine("文件 {0} 下载失败", imgName);
            }
            string contentType = webClient.ResponseHeaders.Get("Content-Type");
            Console.WriteLine("文件下载成功！");
            Console.WriteLine("文件类型：" + contentType);
            webClient.Dispose();
        }
    }
}

 

 

 

谢谢浏览！