转自原文 【C#】HTTP请求GET，POST
HTTP定义了与服务器交互的不同方法，基本方法有GET，POST，PUT，DELETE，分别对于查，该，增，删。一般情况下我们只用到GET和POST，其他两种都也可以用GET和POST来实现，很多浏览器也只实现了GET和POST两种方法
GET：用户获取信息
安全的：不会对服务器上的数据进行修改，和破坏
幂等的：相同的请求所返回的结果相同
参数是通过Url来传输，接在Url后面中间用?分开，不同参数之间用&分开，下面表示传递两个参数param1和param2，值为value1和value2
http://songurl/index.htm?param1=value1¶m2=value2
通过上面可以看到，GET请求数据在隐私方面又是不安全的，因为Url上的信息可以直接让用户看到，这样不利于隐私保护
POST：用于更新数据
传递的数据对用户隐藏，封装在包里，具体看演示
有时候请求会重定向，但我们就需要从重定向url获取东西，这时可以设置重定向禁用，你就可以从headers的Location属性中获取重定向地址
request.AllowAutoRedirect = false;
string[] values = request.Headers.GetValues("Location");
下面是辅助类的定义
public class HttpHelper { /// <summary> /// 创建GET方式的HTTP请求 /// </summary> public static HttpWebResponse CreateGetHttpResponse(string url, int timeout, string userAgent, CookieCollection cookies) { HttpWebRequest request = null; if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase)) { //对服务端证书进行有效性校验（非第三方权威机构颁发的证书，如自己生成的，不进行验证，这里返回true） ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult); request = WebRequest.Create(url) as HttpWebRequest; request.ProtocolVersion = HttpVersion.Version10; //http版本，默认是1.1,这里设置为1.0 } else { request = WebRequest.Create(url) as HttpWebRequest; } request.Method = "GET"; //设置代理UserAgent和超时 //request.UserAgent = userAgent; //request.Timeout = timeout; if (cookies != null) { request.CookieContainer = new CookieContainer(); request.CookieContainer.Add(cookies); } return request.GetResponse() as HttpWebResponse; } /// <summary> /// 创建POST方式的HTTP请求 /// </summary> public static HttpWebResponse CreatePostHttpResponse(string url, IDictionary<string, string> parameters, int timeout, string userAgent, CookieCollection cookies) { HttpWebRequest request = null; //如果是发送HTTPS请求 if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase)) { //ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult); request = WebRequest.Create(url) as HttpWebRequest; //request.ProtocolVersion = HttpVersion.Version10; } else { request = WebRequest.Create(url) as HttpWebRequest; } request.Method = "POST"; request.ContentType = "application/x-www-form-urlencoded"; //设置代理UserAgent和超时 //request.UserAgent = userAgent; //request.Timeout = timeout; if (cookies != null) { request.CookieContainer = new CookieContainer(); request.CookieContainer.Add(cookies); } //发送POST数据 if (!(parameters == null || parameters.Count == 0)) { StringBuilder buffer = new StringBuilder(); int i = 0; foreach (string key in parameters.Keys) { if (i > 0) { buffer.AppendFormat("&{0}={1}", key, parameters[key]); } else { buffer.AppendFormat("{0}={1}", key, parameters[key]); i++; } } byte[] data = Encoding.ASCII.GetBytes(buffer.ToString()); using (Stream stream = request.GetRequestStream()) { stream.Write(data, 0, data.Length); } } string[] values = request.Headers.GetValues("Content-Type"); return request.GetResponse() as HttpWebResponse; } /// <summary> /// 获取请求的数据 /// </summary> public static string GetResponseString(HttpWebResponse webresponse) { using (Stream s = webresponse.GetResponseStream()) { StreamReader reader = new StreamReader(s, Encoding.UTF8); return reader.ReadToEnd(); } } /// <summary> /// 验证证书 /// </summary> private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors) { if (errors == SslPolicyErrors.None) return true; return false; } }
没有整理与归纳的知识，一文不值！高度概括与梳理的知识，才是自己真正的知识与技能。 永远不要让自己的自由、好奇、充满创造力的想法被现实的框架所束缚，让创造力自由成长吧！ 多花时间，关心他（她）人，正如别人所关心你的。理想的腾飞与实现，没有别人的支持与帮助，是万万不能的。
本文转自wenglabs博客园博客，原文链接：http://www.cnblogs.com/arxive/p/7073444.html
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