一、HttpWebRequest简介

1. HttpWebRequest和HttpWebResponse对比

1、HttpWebRequest和HttpWebResponse类是用于发送和接收HTTP数据的最好选择。 2、命名空间:System.Net 3、HttpWebRequest对象不是利用new关键字创建的(通过构造函数)。
而是利用Create()方法创建的。 4、你可能预计需要显示地调用一个“Send”方法,实际上不需要。 5、调用 HttpWebRequest.GetResponse()方法返回的是一个HttpWebResponse对象 6、你可以把HTTP响应的数据流 (stream)绑定到一个StreamReader对象,然后就可以通过ReadToEnd()方法把整个HTTP响应作为一个字符串取回。也可以通过 StreamReader.ReadLine()方法逐行取回HTTP响应的内容。

2. HttpWebRequest属性

下面是HttpWebRequest的一些属性,这些属性对于轻量级的自动化测试程序是非常重要的。
  • AllowAutoRedirect:获取或设置一个值,该值指示请求是否应跟随重定向响应。
  • CookieContainer:获取或设置与此请求关联的cookie。
  • Credentials:获取或设置请求的身份验证信息。
  • KeepAlive:获取或设置一个值,该值指示是否与 Internet 资源建立持久性连接。
  • MaximumAutomaticRedirections:获取或设置请求将跟随的重定向的最大数目。
  • Proxy:获取或设置请求的代理信息。
  • SendChunked:获取或设置一个值,该值指示是否将数据分段发送到 Internet 资源。
  • Timeout:获取或设置请求的超时值。
  • UserAgent:获取或设置 User-agent HTTP 标头的值

二、HttpWebRequest请求接口

HttpWebRequest提交数据方式其实就是GET和POST两种

1. HttpWebRequest的作用:

HttpWebRequest对HTTP协议进行了完整的封装,对HTTP协议中的 Header, Content, Cookie 都做了属性和方法的支持,很容易就能编写出一个模拟浏览器自动登录的程序。

2. HttpWebRequest提交数据方式:

程序使用HTTP协议和服务器交互主要是进行数据的提交,通常数据的提交是通过 GET 和 POST 两种方式来完成,
1. GET 方式。
GET方式通过在网络地址附加参数来完成数据提交,比如在地址http://www.google.com/webhp?hl=zh-CN中,前面部分http://www.google.com/webhp表示数据提交的网址,后面部分<font style="color:rgb(77, 77, 77);"> hl=zh-CN</font> 表示附加的参数,其中 hl 表示一个键(key), zh-CN 表示这个键对应的值(value)。程序代码如下:
  1. HttpWebRequest req =
  2. (HttpWebRequest)HttpWebRequest.Create("http://www.google.com/webhp?hl=zh-CN");
  3. req.Method = "GET";
  4. using (WebResponse wr = req.GetResponse())
  5. {
  6. //在这里对接收到的页面内容进行处理
  7. }
  1. string htmlStr = string.Empty;
  2. //创建一个客户端的Http请求实例
  3. HttpWebRequest request = WebRequest.Create(requestUrl) as HttpWebRequest;
  4. request.Method = "GET";
  5. //获取当前Http请求的响应实例
  6. HttpWebResponse response = request.GetResponse() as HttpWebResponse;
  7. Stream responseStream = response.GetResponseStream();
  8. using (StreamReader reader = new StreamReader(responseStream, Encoding.GetEncoding("UTF-8")))
  9. {
  10. htmlStr = reader.ReadToEnd();
  11. }
  12. responseStream.Close();
  13. response.Close();
  14. return htmlStr;
2. POST 方式。
POST 方式通过在页面内容中填写参数的方法来完成数据的提交,参数的格式和 GET 方式一样,是类似于 hl=zh-CN&newwindow=1 这样的结构。程序代码如下:
  1. string param = "hl=zh-CN&newwindow=1"; //参数
  2. byte[] bs = Encoding.ASCII.GetBytes(param); //参数转化为ascii码
  3. HttpWebRequest req =
  4. (HttpWebRequest) HttpWebRequest.Create("http://www.google.com/intl/zh-CN/" ); //创建request
  5. req.Method = "POST"; //确定传值的方式,此处为post方式传值
  6. req.ContentType = "application/x-www-form-urlencoded";
  7. req.ContentLength = bs.Length;
  8. using (Stream reqStream = req.GetRequestStream())
  9. {
  10. reqStream.Write(bs, 0, bs.Length);
  11. }
  12. using (WebResponse wr = req.GetResponse())
  13. {
  14. //在这里对接收到的页面内容进行处理
  15. }
3. 使用 GET 方式提交中文数据。
GET 方式通过在网络地址中附加参数来完成数据提交,对于中文的编码,常用的有 gb2312 和 utf8 两种,用 gb2312 方式编码访问的程序代码如下:
  1. Encoding myEncoding = Encoding.GetEncoding("gb2312"); //确定用哪种中文编码方式
  2. string address = "http://www.baidu.com/s?"+ HttpUtility.UrlEncode("参数一", myEncoding) + "=" + HttpUtility.UrlEncode("值一", myEncoding); //拼接数据提交的网址和经过中文编码后的中文参数
  3. HttpWebRequest req =
  4. (HttpWebRequest)HttpWebRequest.Create(address); //创建request
  5. req.Method = "GET"; //确定传值方式,此处为get方式
  6. using (WebResponse wr = req.GetResponse())
  7. {
  8. //在这里对接收到的页面内容进行处理
  9. }
在上面的程序代码中,我们以 GET 方式访问了网址 http://www.baidu.com/s ,传递了参数“参数一=值一”,由于无法告知对方提交数据的编码类型,所以编码方式要以对方的网站为标准。常见的网站中, www.baidu.com (百度)的编码方式是 gb2312, www.google.com (谷歌)的编码方式是 utf8。
4. 使用 POST 方式提交中文数据。
POST 方式通过在页面内容中填写参数的方法来完成数据的提交,由于提交的参数中可以说明使用的编码方式,所以理论上能获得更大的兼容性。用 gb2312 方式编码访问的程序代码如下:
  1. Encoding myEncoding = Encoding.GetEncoding("gb2312"); //确定中文编码方式。此处用gb2312
  2. string param = HttpUtility.UrlEncode("参数一", myEncoding) + "=" + HttpUtility.UrlEncode("值一", myEncoding) + "&" + HttpUtility.UrlEncode("参数二", myEncoding) + "=" + HttpUtility.UrlEncode("值二", myEncoding);
  3. byte[] postBytes = Encoding.ASCII.GetBytes(param); //将参数转化为assic码
  4. HttpWebRequest req =
  5. (HttpWebRequest) HttpWebRequest.Create( "http://www.baidu.com/s" );
  6. req.Method = "POST";
  7. req.ContentType = "application/x-www-form-urlencoded;charset=gb2312";
  8. req.ContentLength = postBytes.Length;
  9. using (Stream reqStream = req.GetRequestStream())
  10. {
  11. reqStream.Write(bs, 0, bs.Length);
  12. }
  13. using (WebResponse wr = req.GetResponse())
  14. {
  15. //在这里对接收到的页面内容进行处理
  16. }
从上面的代码可以看出, POST 中文数据的时候,先使用 UrlEncode 方法将中文字符转换为编码后的 ASCII 码,然后提交到服务器,提交的时候可以说明编码的方式,用来使对方服务器能够正确的解析。 以上列出了客户端程序使用HTTP协议与服务器交互的情况,常用的是 GET 和 POST 方式。 现在流行的 WebService 也是通过 HTTP 协议来交互的,使用的是 POST 方法。与以上稍有所不同的是, WebService 提交的数据内容和接收到的数据内容都是使用了 XML 方式编码。所以, HttpWebRequest 也可以使用在调用 WebService 的情况下。 C# HttpWebRequest提交数据方式的基本内容就向你介绍到这里,希望对你了解和学习C# HttpWebRequest提交数据方式有所帮助。

四、完整示例

1. demo

  1. #region 公共方法
  2. /// <summary>
  3. /// Get数据接口
  4. /// </summary>
  5. /// <param name="getUrl">接口地址</param>
  6. /// <returns></returns>
  7. private static string GetWebRequest(string getUrl)
  8. {
  9. string responseContent = "";
  10. HttpWebRequest request = (HttpWebRequest)WebRequest.Create(getUrl);
  11. request.ContentType = "application/json";
  12. request.Method = "GET";
  13. HttpWebResponse response = (HttpWebResponse)request.GetResponse();
  14. //在这里对接收到的页面内容进行处理
  15. using (Stream resStream = response.GetResponseStream())
  16. {
  17. using (StreamReader reader = new StreamReader(resStream, Encoding.UTF8))
  18. {
  19. responseContent = reader.ReadToEnd().ToString();
  20. }
  21. }
  22. return responseContent;
  23. }
  24. /// <summary>
  25. /// Post数据接口
  26. /// </summary>
  27. /// <param name="postUrl">接口地址</param>
  28. /// <param name="paramData">提交json数据</param>
  29. /// <param name="dataEncode">编码方式(Encoding.UTF8)</param>
  30. /// <returns></returns>
  31. private static string PostWebRequest(string postUrl, string paramData, Encoding dataEncode)
  32. {
  33. string responseContent = string.Empty;
  34. try
  35. {
  36. byte[] byteArray = dataEncode.GetBytes(paramData); //转化
  37. HttpWebRequest webReq = (HttpWebRequest)WebRequest.Create(new Uri(postUrl));
  38. webReq.Method = "POST";
  39. webReq.ContentType = "application/x-www-form-urlencoded";
  40. webReq.ContentLength = byteArray.Length;
  41. using (Stream reqStream = webReq.GetRequestStream())
  42. {
  43. reqStream.Write(byteArray, 0, byteArray.Length);//写入参数
  44. //reqStream.Close();
  45. }
  46. using (HttpWebResponse response = (HttpWebResponse)webReq.GetResponse())
  47. {
  48. //在这里对接收到的页面内容进行处理
  49. using (StreamReader sr = new StreamReader(response.GetResponseStream(), Encoding.Default))
  50. {
  51. responseContent = sr.ReadToEnd().ToString();
  52. }
  53. }
  54. }
  55. catch (Exception ex)
  56. {
  57. return ex.Message;
  58. }
  59. return responseContent;
  60. }
  61. #endregion

2. post支持cookie

  1. /// <summary>
  2. /// 发起Post请求(采用HttpWebRequest,支持传Cookie)
  3. /// </summary>
  4. /// <param name="strUrl">请求Url</param>
  5. /// <param name="formData">发送的表单数据</param>
  6. /// <param name="strResult">返回请求结果(如果请求失败,返回异常消息)</param>
  7. /// <param name="cookieContainer">随同HTTP请求发送的Cookie信息,如果不需要身份验证可以为空</param>
  8. /// <returns>返回:是否请求成功</returns>
  9. public static bool HttpPost(string strUrl, Dictionary<string, string> formData, CookieContainer cookieContainer, out string strResult)
  10. {
  11. string strPostData = null;
  12. if (formData != null && formData.Count > 0)
  13. {
  14. StringBuilder sbData = new StringBuilder();
  15. int i = 0;
  16. foreach (KeyValuePair<string, string> data in formData)
  17. {
  18. if (i > 0)
  19. {
  20. sbData.Append("&");
  21. }
  22. sbData.AppendFormat("{0}={1}", data.Key, data.Value);
  23. i++;
  24. }
  25. strPostData = sbData.ToString();
  26. }
  27. byte[] postBytes = string.IsNullOrEmpty(strPostData) ? new byte[0] : Encoding.UTF8.GetBytes(strPostData);
  28. return HttpPost(strUrl, postBytes, cookieContainer, out strResult);
  29. }

3. post上传文件

  1. /// <summary>
  2. /// 发起Post文件请求(采用HttpWebRequest,支持传Cookie)
  3. /// </summary>
  4. /// <param name="strUrl">请求Url</param>
  5. /// <param name="strFilePostName">上传文件的PostName</param>
  6. /// <param name="strFilePath">上传文件路径</param>
  7. /// <param name="cookieContainer">随同HTTP请求发送的Cookie信息,如果不需要身份验证可以为空</param>
  8. /// <param name="strResult">返回请求结果(如果请求失败,返回异常消息)</param>
  9. /// <returns>返回:是否请求成功</returns>
  10. public static bool HttpPostFile(string strUrl, string strFilePostName, string strFilePath, CookieContainer cookieContainer, out string strResult)
  11. {
  12. HttpWebRequest request = null;
  13. FileStream fileStream = FileHelper.GetFileStream(strFilePath);
  14. try
  15. {
  16. if (fileStream == null)
  17. {
  18. throw new FileNotFoundException();
  19. }
  20. request = (HttpWebRequest)WebRequest.Create(strUrl);
  21. request.Method = "POST";
  22. request.KeepAlive = false;
  23. request.Timeout = 30000;
  24. if (cookieContainer != null)
  25. {
  26. request.CookieContainer = cookieContainer;
  27. }
  28. string boundary = string.Format("---------------------------{0}", DateTime.Now.Ticks.ToString("x"));
  29. byte[] header = Encoding.UTF8.GetBytes(string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}\"\r\nContent-Type: application/octet-stream\r\n\r\n",
  30. boundary, strFilePostName, Path.GetFileName(strFilePath)));
  31. byte[] footer = Encoding.UTF8.GetBytes(string.Format("\r\n--{0}--\r\n", boundary));
  32. request.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);
  33. request.ContentLength = header.Length + fileStream.Length + footer.Length;
  34. using (Stream reqStream = request.GetRequestStream())
  35. {
  36. // 写入分割线及数据信息
  37. reqStream.Write(header, 0, header.Length);
  38. // 写入文件
  39. FileHelper.WriteFile(reqStream, fileStream);
  40. // 写入尾部
  41. reqStream.Write(footer, 0, footer.Length);
  42. }
  43. strResult = GetResponseResult(request, cookieContainer);
  44. }
  45. catch (Exception ex)
  46. {
  47. strResult = ex.Message;
  48. return false;
  49. }
  50. finally
  51. {
  52. if (request != null)
  53. {
  54. request.Abort();
  55. }
  56. if (fileStream != null)
  57. {
  58. fileStream.Close();
  59. }
  60. }
  61. return true;
  62. }
  63. /// <summary>
  64. /// 获取请求结果字符串
  65. /// </summary>
  66. /// <param name="request">请求对象(发起请求之后)</param>
  67. /// <param name="cookieContainer">随同HTTP请求发送的Cookie信息,如果不需要身份验证可以为空</param>
  68. /// <returns>返回请求结果字符串</returns>
  69. private static string GetResponseResult(HttpWebRequest request, CookieContainer cookieContainer = null)
  70. {
  71. using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
  72. {
  73. if (cookieContainer != null)
  74. {
  75. response.Cookies = cookieContainer.GetCookies(response.ResponseUri);
  76. }
  77. using (Stream rspStream = response.GetResponseStream())
  78. {
  79. using (StreamReader reader = new StreamReader(rspStream, Encoding.UTF8))
  80. {
  81. return reader.ReadToEnd();
  82. }
  83. }
  84. }
  85. }

4. OAuth头部

  1. //构造OAuth头部
  2. StringBuilder oauthHeader = new StringBuilder();
  3. oauthHeader.AppendFormat("OAuth realm=\"\", oauth_consumer_key={0}, ", apiKey);
  4. oauthHeader.AppendFormat("oauth_nonce={0}, ", nonce);
  5. oauthHeader.AppendFormat("oauth_timestamp={0}, ", timeStamp);
  6. oauthHeader.AppendFormat("oauth_signature_method={0}, ", "HMAC-SHA1");
  7. oauthHeader.AppendFormat("oauth_version={0}, ", "1.0");
  8. oauthHeader.AppendFormat("oauth_signature={0}, ", sig);
  9. oauthHeader.AppendFormat("oauth_token={0}", accessToken);
  10. //构造请求
  11. StringBuilder requestBody = new StringBuilder("");
  12. Encoding encoding = Encoding.GetEncoding("utf-8");
  13. byte[] data = encoding.GetBytes(requestBody.ToString());
  14. // Http Request的设置
  15. HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
  16. request.Headers.Set("Authorization", oauthHeader.ToString());
  17. //request.Headers.Add("Authorization", authorization);
  18. request.ContentType = "application/atom+xml";
  19. request.Method = "GET";

五、C#通过WebClient/HttpWebRequest实现http的post/get方法

1. POST方法(httpWebRequest)

  1. //body是要传递的参数,格式"roleId=1&uid=2"
  2. //post的cotentType填写:"application/x-www-form-urlencoded"
  3. //soap填写:"text/xml; charset=utf-8"
  4. public static string PostHttp(string url, string body, string contentType)
  5. {
  6. HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
  7. httpWebRequest.ContentType = contentType;
  8. httpWebRequest.Method = "POST";
  9. httpWebRequest.Timeout = 20000;
  10. byte[] btBodys = Encoding.UTF8.GetBytes(body);
  11. httpWebRequest.ContentLength = btBodys.Length;
  12. httpWebRequest.GetRequestStream().Write(btBodys, 0, btBodys.Length);
  13. HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
  14. StreamReader streamReader = new StreamReader(httpWebResponse.GetResponseStream());
  15. string responseContent = streamReader.ReadToEnd();
  16. httpWebResponse.Close();
  17. streamReader.Close();
  18. httpWebRequest.Abort();
  19. httpWebResponse.Close();
  20. return responseContent;
  21. }

2. POST方法(WebClient)

  1. /// <summary>
  2. /// 通过WebClient类Post数据到远程地址,需要Basic认证;
  3. /// 调用端自己处理异常
  4. /// </summary>
  5. /// <param name="uri"></param>
  6. /// <param name="paramStr">name=张三&age=20</param>
  7. /// <param name="encoding">请先确认目标网页的编码方式</param>
  8. /// <param name="username"></param>
  9. /// <param name="password"></param>
  10. /// <returns></returns>
  11. public static string Request_WebClient(string uri, string paramStr, Encoding encoding, string username, string password)
  12. {
  13. if (encoding == null)
  14. encoding = Encoding.UTF8;
  15. string result = string.Empty;
  16. WebClient wc = new WebClient();
  17. // 采取POST方式必须加的Header
  18. wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
  19. byte[] postData = encoding.GetBytes(paramStr);
  20. if (!string.IsNullOrEmpty(username) && !string.IsNullOrEmpty(password))
  21. {
  22. wc.Credentials = GetCredentialCache(uri, username, password);
  23. wc.Headers.Add("Authorization", GetAuthorization(username, password));
  24. }
  25. byte[] responseData = wc.UploadData(uri, "POST", postData); // 得到返回字符流
  26. return encoding.GetString(responseData);// 解码
  27. }

3. Get方法(httpWebRequest)

  1. public static string GetHttp(string url, HttpContext httpContext)
  2. {
  3. string queryString = "?";
  4. foreach (string key in httpContext.Request.QueryString.AllKeys)
  5. {
  6. queryString += key + "=" + httpContext.Request.QueryString[key] + "&";
  7. }
  8. queryString = queryString.Substring(0, queryString.Length - 1);
  9. HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url + queryString);
  10. httpWebRequest.ContentType = "application/json";
  11. httpWebRequest.Method = "GET";
  12. httpWebRequest.Timeout = 20000;
  13. //byte[] btBodys = Encoding.UTF8.GetBytes(body);
  14. //httpWebRequest.ContentLength = btBodys.Length;
  15. //httpWebRequest.GetRequestStream().Write(btBodys, 0, btBodys.Length);
  16. HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
  17. StreamReader streamReader = new StreamReader(httpWebResponse.GetResponseStream());
  18. string responseContent = streamReader.ReadToEnd();
  19. httpWebResponse.Close();
  20. streamReader.Close();
  21. return responseContent;
  22. }

4. basic验证的WebRequest/WebResponse

  1. /// <summary>
  2. /// 通过 WebRequest/WebResponse 类访问远程地址并返回结果,需要Basic认证;
  3. /// 调用端自己处理异常
  4. /// </summary>
  5. /// <param name="uri"></param>
  6. /// <param name="timeout">访问超时时间,单位毫秒;如果不设置超时时间,传入0</param>
  7. /// <param name="encoding">如果不知道具体的编码,传入null</param>
  8. /// <param name="username"></param>
  9. /// <param name="password"></param>
  10. /// <returns></returns>
  11. public static string Request_WebRequest(string uri, int timeout, Encoding encoding, string username, string password)
  12. {
  13. string result = string.Empty;
  14. WebRequest request = WebRequest.Create(new Uri(uri));
  15. if (!string.IsNullOrEmpty(username) && !string.IsNullOrEmpty(password))
  16. {
  17. request.Credentials = GetCredentialCache(uri, username, password);
  18. request.Headers.Add("Authorization", GetAuthorization(username, password));
  19. }
  20. if (timeout > 0)
  21. request.Timeout = timeout;
  22. WebResponse response = request.GetResponse();
  23. Stream stream = response.GetResponseStream();
  24. StreamReader sr = encoding == null ? new StreamReader(stream) : new StreamReader(stream, encoding);
  25. result = sr.ReadToEnd();
  26. sr.Close();
  27. stream.Close();
  28. return result;
  29. }
  30. #region # 生成 Http Basic 访问凭证 #
  31. private static CredentialCache GetCredentialCache(string uri, string username, string password)
  32. {
  33. string authorization = string.Format("{0}:{1}", username, password);
  34. CredentialCache credCache = new CredentialCache();
  35. credCache.Add(new Uri(uri), "Basic", new NetworkCredential(username, password));
  36. return credCache;
  37. }
  38. private static string GetAuthorization(string username, string password)
  39. {
  40. string authorization = string.Format("{0}:{1}", username, password);
  41. return "Basic " + Convert.ToBase64String(new ASCIIEncoding().GetBytes(authorization));
  42. }
  43. #endregion

六、遇见问题

1. post数据时报错:远程服务器返回错误: (400) 错误的请求

报400说是传的数据格式不对

Content_Type为:application/json,配的数据格式有些麻烦,特别数多层,单层还好。
例如,我本传的数据是这个的json:

  1. {
  2. "key1": {
  3. "key11": "value11",
  4. "key12": "value12"
  5. },
  6. "key2": "value2"
  7. }
这时候,postData应该为:{“key1”: {\”key11\”: \”value11\”,\”key12\”: \”value12\”},”key2”: “value2”} c#里赋值写法为:(这里建议将json格式数据通过json工具转义,避免自己转移带来不必要的错误)
  1. {
  2. \"key1\": {
  3. \"key11\": \"value11\",
  4. \"key12\": \"value12\"
  5. },
  6. \"key2\": \"value2\"
  7. }
post的方法:
  1. protected string PostUrl(string url, string postData)
  2. {
  3. try
  4. {
  5. HttpWebRequest webrequest = (HttpWebRequest)HttpWebRequest.Create(url);
  6. webrequest.Method = "post";
  7. webrequest.ContentType = "application/json;charset=utf-8";
  8. byte[] postdatabyte = Encoding.UTF8.GetBytes(postData);
  9. webrequest.ContentLength = postdatabyte.Length;
  10. Stream stream;
  11. stream = webrequest.GetRequestStream();
  12. stream.Write(postdatabyte, 0, postdatabyte.Length);
  13. stream.Close();
  14. using (var httpWebResponse = webrequest.GetResponse())
  15. using (StreamReader responseStream = new StreamReader(httpWebResponse.GetResponseStream()))
  16. {
  17. String ret = responseStream.ReadToEnd();
  18. string result = ret.ToString();
  19. return result;
  20. }
  21. }
  22. catch (Exception ex)
  23. {
  24. HttpContext.Current.Response.Write(ex);
  25. return "";
  26. }
  27. }
如果posData的格式写错,运行后报错(using (var httpWebResponse = webrequest.GetResponse())):System.Net.WebException: 远程服务器返回错误: (400) 错误的请求。 在System.Net.HttpWebRequest.GetResponse() 。