HttpClient使用

　　以京训钉开发平台接口文档为例，使用HttpClient类请求调用其接口，对数据进行增删改查等操作。
　　文档地址：https://www.yuque.com/bjjnts/jxd/bo1osz using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Text; using System.Threading.Tasks; using System.Web.Caching;  namespace JxdService {     public class JxdService     {         private static HttpClient httpClient;          static JxdService()         {             httpClient = new HttpClient();             httpClient.BaseAddress = new Uri(＂https://openapi.bjjnts.cn＂);             //httpClient.DefaultRequestHeaders.Add(＂Authorization＂, ＂xxxxxxxx＂);         }          public static object _tokenLocker = new object();         public static Token Token         {             get             {                 lock (_tokenLocker)                 {                     var cache = new Cache();                     var token = cache.Get(＂jxd_token＂) as Token;                     if (token == null)                     {                         token = GetToken();                         cache.Insert(＂jxd_token＂, token, null, DateTime.Now.AddSeconds(token.expires_in - 10 * 60), Cache.NoSlidingExpiration);                     }                     return token;                 }             }         }          /// 
         /// 获取Token         /// 
         ///          public static Token GetToken()         {             HttpContent content = new StringContent(＂{＂app_key＂:＂YGnTIDznnAdS9bYf＂, ＂app_secret＂:＂lxFboer5sxUlpFTDpHLdLU8mlkWabLYy＂}＂, Encoding.UTF8, ＂application/json＂);              var httpResponse = httpClient.PostAsync(＂/token＂, content).Result;             var result = ＂＂;             if (httpResponse.StatusCode == System.Net.HttpStatusCode.OK)             {                 result = httpResponse.Content.ReadAsStringAsync().Result;             }              if (string.IsNullOrWhiteSpace(result))             {                 return null;             }             var token = JsonHelper.Deserializer(result);             return token;         }          /// 
         /// 清除Token         /// 
         private static void ClearToken()         {             var cache = new Cache();             cache.Remove(＂jxd_token＂);         }           /// 
         /// 获取课程资源         /// 
         ///          public static List GetCoruses(CourseInfo where)         {             var token = Token;             httpClient.DefaultRequestHeaders.Remove(＂Authorization＂);             httpClient.DefaultRequestHeaders.Add(＂Authorization＂, #34;{token.token_type} {token.access_token}＂);              var httpResponse = httpClient.GetAsync(＂/courses?title=＂ + where.title).Result;              //校验Token是否有效             if (httpResponse.StatusCode == System.Net.HttpStatusCode.Unauthorized)             {                 ClearToken();                 return GetCoruses(where);             }              var result = ＂＂;             if (httpResponse.StatusCode == System.Net.HttpStatusCode.OK)             {                 result = httpResponse.Content.ReadAsStringAsync().Result;             }              if (string.IsNullOrWhiteSpace(result))             {                 return null;             }             return JsonHelper.Deserializer>(result);         }                   /// 
         /// 获取课程资源         /// 
         ///          public static CourseInfo GetCoruse(int id)         {             var token = Token;             httpClient.DefaultRequestHeaders.Remove(＂Authorization＂);             httpClient.DefaultRequestHeaders.Add(＂Authorization＂, #34;{token.token_type} {token.access_token}＂);              var httpResponse = httpClient.GetAsync(#34;/courses/{id}＂).Result;             //校验Token是否有效             if (httpResponse.StatusCode == System.Net.HttpStatusCode.Unauthorized)             {                 ClearToken();                 return GetCoruse(id);             }              var result = ＂＂;             if (httpResponse.StatusCode == System.Net.HttpStatusCode.OK)             {                 result = httpResponse.Content.ReadAsStringAsync().Result;             }              if (string.IsNullOrWhiteSpace(result))             {                 return null;             }             return JsonHelper.Deserializer(result);         }          /// 
         /// 添加课程资源         /// 
         ///          public static CourseInfo AddCoruse(CourseVm course)         {             var token = Token;             httpClient.DefaultRequestHeaders.Remove(＂Authorization＂);             httpClient.DefaultRequestHeaders.Add(＂Authorization＂, #34;{token.token_type} {token.access_token}＂);              var data = JsonHelper.SerializeObject(new { course.title, course.image, course.job_id, course.copyright_id, course.content, course.cost_price });              var httpResponse = httpClient.PostAsync(＂/courses＂, new StringContent(data, Encoding.UTF8, ＂application/json＂)).Result;             //校验Token是否有效             if (httpResponse.StatusCode == System.Net.HttpStatusCode.Unauthorized)             {                 ClearToken();                 return AddCoruse(course);             }              var result = ＂＂;             if (httpResponse.StatusCode == System.Net.HttpStatusCode.Created)             {                 result = httpResponse.Content.ReadAsStringAsync().Result;             }              if (string.IsNullOrWhiteSpace(result))             {                 return null;             }             return JsonHelper.Deserializer(result);         }          /// 
         /// 修改课程         /// 
         ///          public static CourseInfo EidtCoruse(CourseVm course)         {             var token = Token;             httpClient.DefaultRequestHeaders.Remove(＂Authorization＂);             httpClient.DefaultRequestHeaders.Add(＂Authorization＂, #34;{token.token_type} {token.access_token}＂);              var data = JsonHelper.SerializeObject(new { course.title, course.image, course.job_id, course.copyright_id, course.content, course.cost_price });              var httpResponse = httpClient.PutAsync(#34;/courses/{course.id}＂, new StringContent(data, Encoding.UTF8, ＂application/json＂)).Result;             //校验Token是否有效             if (httpResponse.StatusCode == System.Net.HttpStatusCode.Unauthorized)             {                 ClearToken();                 return EidtCoruse(course);             }              var result = ＂＂;             if (httpResponse.StatusCode == System.Net.HttpStatusCode.OK)             {                 result = httpResponse.Content.ReadAsStringAsync().Result;             }              if (string.IsNullOrWhiteSpace(result))             {                 return null;             }             return JsonHelper.Deserializer(result);         }          /// 
         /// 删除课程         /// 
         ///          public static bool DelCoruse(int courseId)         {             var token = Token;             httpClient.DefaultRequestHeaders.Remove(＂Authorization＂);             httpClient.DefaultRequestHeaders.Add(＂Authorization＂, #34;{token.token_type} {token.access_token}＂);              var httpResponse = httpClient.DeleteAsync(#34;/courses/{courseId}＂).Result;             //校验Token是否有效             if (httpResponse.StatusCode == System.Net.HttpStatusCode.Unauthorized)             {                 ClearToken();                 return DelCoruse(courseId);             }              return httpResponse.StatusCode == System.Net.HttpStatusCode.NoContent;         }     } }