HttpWebRequest 请求带OAuth2 授权的webapi

OAuth 2.0注意事项： 
1、 获取access_token时，请使用POST

1  private static string GetAuthorization(string username, string password)
2         {
3             string authorization = string.Format("{0}:{1}", username, password);
4 
5             return "Basic " + Convert.ToBase64String(new ASCIIEncoding().GetBytes(authorization));
6         }

 1   /// <summary>
 2         /// 获取Token
 3         /// </summary>
 4         /// <returns></returns>
 5         private static string OAuthClientCredentialsToken()
 6         {
 7             const string clientId = "8518";
 8             const string clientSecret = "8518";
 9             string result = string.Empty;
10 
11             HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(_baseUrl + "/token");
12             httpWebRequest.Method = "POST";
13             httpWebRequest.ContentType = "application/x-www-form-urlencoded";
14             httpWebRequest.Accept = "application/json";
15             httpWebRequest.Timeout = 15000;
16             httpWebRequest.KeepAlive = false;
17             httpWebRequest.AllowAutoRedirect = true;
18             // httpWebRequest.Headers.Add("Accept-Language", "zh-cn");
19             //  httpWebRequest.Headers.Add("Accept-Encoding", "gzip, deflate");
20             // httpWebRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.1.4322)";
21             httpWebRequest.Headers.Add("Authorization", GetAuthorization(clientId, clientSecret));
22             //Credentials
23             httpWebRequest.Credentials = CredentialCache.DefaultCredentials;
24             //post参数
25             StringBuilder postParam = new StringBuilder();
26             Dictionary<string, string> parameters = new Dictionary<string, string> { { "grant_type", "client_credentials" } };
27             int i = 0;
28             foreach (KeyValuePair<string, string> parameter in parameters)
29             {
30                 if (i > 0)
31                     postParam.Append("&");
32                 postParam.AppendFormat("{0}={1}", parameter.Key, HttpUtility.UrlEncode(parameter.Value));
33                 i++;
34             }
35 
36             byte[] postData = Encoding.UTF8.GetBytes(postParam.ToString());
37             httpWebRequest.ContentLength = postData.Length;
38 
39             try
40             {
41                 Stream requesStream = httpWebRequest.GetRequestStream();
42                 requesStream.Write(postData, 0, postData.Length);
43                 requesStream.Close();
44 
45                 WebResponse response = httpWebRequest.GetResponse();
46                 Stream stream = response.GetResponseStream();
47                 if (stream != null)
48                 {
49                     using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))
50                     {
51                         result = reader.ReadToEnd();
52                         reader.Close();
53                     }
54                     stream.Close();
55                 }
56             }
57             catch (WebException ex)
58             {
59                 throw new Exception(ex.Message);
60             }
61             return !string.IsNullOrWhiteSpace(result) ? JObject.Parse(result)["access_token"].Value<string>() : result;
62         }

2、 访问需要授权的Api，请使用http/https协议，并且加上access token的Header 
3 、Header格式为"Authorization: Bearer access_token"，其中Bearer后面有一个空格

 1  /// <summary>
 2         /// HttpGet
 3         /// </summary>
 4         /// <param name="url"></param>
 5         /// <param name="token"></param>
 6         /// <param name="contentType"></param>
 7         /// <returns></returns>
 8         private static string HttpGet(string url, string token, string contentType = "application/x-www-form-urlencoded")
 9         {
10             HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
11             httpWebRequest.Method = "GET";
12             httpWebRequest.ContentType = contentType;
13             httpWebRequest.Accept = "application/json";
14             httpWebRequest.Timeout = 15000;
15             httpWebRequest.AllowAutoRedirect = false;
16             //Bearer+空格
17             httpWebRequest.Headers.Add("Authorization", "Bearer " + token);
18             httpWebRequest.Credentials = CredentialCache.DefaultCredentials;
19 
20             string result = null;
21             try
22             {
23                 WebResponse response = httpWebRequest.GetResponse();
24                 Stream responseStream = response.GetResponseStream();
25                 if (responseStream != null)
26                 {
27                     using (StreamReader streamReader = new StreamReader(responseStream, Encoding.UTF8))
28                     {
29                         result = streamReader.ReadToEnd();
30                         streamReader.Close();
31                     }
32                 }
33             }
34             catch (Exception ex)
35             {
36                 throw new Exception(ex.Message);
37             }
38             return result;
39         }