C#中的Http访问总结
Posted lionwang
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第一种是最基本的Http访问，这是同步调用，会有延迟和卡顿：
/// <summary> /// 向服务器发送Request /// </summary> /// <param name="url">字符串</param> /// <param name="method">枚举类型的方法Get或者Post</param> /// <param name="body">Post时必须传值</param> /// <param name="timeoutSeconds">超时时间，单位秒</param> /// <returns></returns> public static string Request(string url, MethodEnum method, string body = "", int timeoutSeconds = 15000) { if (!IsConnectedInternet()) return "网络连接错误，请稍后再试。"; try { GC.Collect(); HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); request.Timeout = timeoutSeconds; request.Method = method.ToString(); //如果是Post的话，则设置body if (method == MethodEnum.POST) { request.ContentType = "application/json"; request.KeepAlive = false; byte[] requestBody = Encoding.UTF8.GetBytes(body); request.ContentLength = requestBody.Length; Stream requestStream = request.GetRequestStream(); requestStream.Write(requestBody, 0, requestBody.Length); } return Response(request); } catch (Exception ex) { if (ex.InnerException != null) return ex.InnerException.Message; if (ex.Message.Contains("已取消一个任务")) return "连接服务器超时，请重试"; if (ex.Message.Contains("404")) return "连接服务器404，请重试"; return ex.Message; } } /// <summary> /// 返回Response数据 /// </summary> /// <param name="request"></param> /// <returns></returns> private static string Response(HttpWebRequest request) { HttpWebResponse response = (HttpWebResponse)request.GetResponse(); string jsonRead = ""; if (response.StatusCode != HttpStatusCode.OK) { return response.StatusCode.ToString(); } //接收过程 if (response.GetResponseStream() != null) { StreamReader myStreamReader = new StreamReader(response.GetResponseStream() ?? Stream.Null, Encoding.UTF8); jsonRead = myStreamReader.ReadToEnd(); myStreamReader.Close(); } response.Close(); request.Abort(); return jsonRead; }
第二种是使用HttpClient来实现异步访问：
1 public static async void AsyncPost(string url, string body, Action<RequestResult> callback, int timeoutSeconds = 10) 2 { 3 var requestResult = new RequestResult(); 4 if (!IsConnectedInternet()) 5 { 6 requestResult.Message = "网络连接错误，请稍后再试。"; 7 callback?.Invoke(requestResult); 8 return; 9 } 10 11 try 12 { 13 using (var client = new HttpClient()) 14 { 15 client.Timeout = new TimeSpan(0, 0, timeoutSeconds); 16 //byte[] requestBody = Encoding.UTF8.GetBytes(body); 17 HttpContent content = new StringContent(body); 18 content.Headers.ContentType = new MediaTypeHeaderValue("application/json"); 19 var response = await client.PostAsync(url, content); 20 //确保HTTP成功状态值 21 response.EnsureSuccessStatusCode(); 22 //await异步读取最后的JSON 23 await response.Content.ReadAsStringAsync().ContinueWith(t => 24 { 25 if (t.IsCompleted) 26 { 27 requestResult.IsSuccess = true; 28 requestResult.Result = t.Result; 29 callback?.Invoke(requestResult); 30 } 31 }); 32 } 33 } 34 catch (Exception e) 35 { 36 if (e.InnerException != null) 37 requestResult.Message = e.InnerException.Message; 38 else if (e.Message.Contains("已取消一个任务")) 39 requestResult.Message = "连接服务器超时，请重试"; 40 else if (e.Message.Contains("404")) 41 requestResult.Message = "连接服务器404，请重试"; 42 else 43 requestResult.Message = e.Message; 44 callback?.Invoke(requestResult); 45 } 46 } 47 48 public static async void AsyncGet(string url, Action<RequestResult> callback, int timeoutSeconds = 10) 49 { 50 var requestResult = new RequestResult(); 51 if (!IsConnectedInternet()) 52 { 53 requestResult.Message = "网络连接错误，请稍后再试。"; 54 callback?.Invoke(requestResult); 55 return; 56 } 57 58 try 59 { 60 using (var client = new HttpClient()) 61 { 62 client.Timeout = new TimeSpan(0, 0, timeoutSeconds); 63 var response = await client.GetAsync(url); 64 //确保HTTP成功状态值 65 response.EnsureSuccessStatusCode(); 66 //await异步读取最后的JSON 67 await response.Content.ReadAsStringAsync().ContinueWith(t => 68 { 69 if (t.IsCompleted) 70 { 71 requestResult.IsSuccess = true; 72 requestResult.Result = t.Result; 73 callback?.Invoke(requestResult); 74 } 75 }); 76 } 77 } 78 catch (Exception e) 79 { 80 if (e.InnerException != null) 81 requestResult.Message = e.InnerException.Message; 82 else if (e.Message.Contains("已取消一个任务")) 83 requestResult.Message = "连接服务器超时，请重试"; 84 else if (e.Message.Contains("404")) 85 requestResult.Message = "连接服务器404，请重试"; 86 else 87 requestResult.Message = e.Message; 88 callback?.Invoke(requestResult); 89 } 90 } 91 92 public static async void AsyncPut(string url, string body, Action<RequestResult> callback, int timeoutSeconds = 10) 93 { 94 var requestResult = new RequestResult(); 95 if (!IsConnectedInternet()) 96 { 97 requestResult.Message = "网络连接错误，请稍后再试。"; 98 callback?.Invoke(requestResult); 99 return; 100 } 101 102 try 103 { 104 using (var client = new HttpClient()) 105 { 106 client.Timeout = new TimeSpan(0, 0, timeoutSeconds); 107 HttpContent content = new StringContent(body); 108 content.Headers.ContentType = new MediaTypeHeaderValue("application/json"); 109 var response = await client.PutAsync(url, content); 110 //确保HTTP成功状态值 111 response.EnsureSuccessStatusCode(); 112 //await异步读取最后的JSON 113 await response.Content.ReadAsStringAsync().ContinueWith(t => 114 { 115 if (t.IsCompleted) 116 { 117 requestResult.IsSuccess = true; 118 requestResult.Result = t.Result; 119 callback?.Invoke(requestResult); 120 } 121 }); 122 } 123 } 124 catch (Exception e) 125 { 126 if (e.InnerException != null) 127 requestResult.Message = e.InnerException.Message; 128 else if (e.Message.Contains("已取消一个任务")) 129 requestResult.Message = "连接服务器超时，请重试"; 130 else if (e.Message.Contains("404")) 131 requestResult.Message = "连接服务器404，请重试"; 132 else 133 requestResult.Message = e.Message; 134 callback?.Invoke(requestResult); 135 } 136 } 137 138 public static async void AsyncDelete(string url, Action<RequestResult> callback, int timeoutSeconds = 10) 139 { 140 var requestResult = new RequestResult(); 141 if (!IsConnectedInternet()) 142 { 143 requestResult.Message = "网络连接错误，请稍后再试。"; 144 callback?.Invoke(requestResult); 145 return; 146 } 147 148 try 149 { 150 using (var client = new HttpClient()) 151 { 152 client.Timeout = new TimeSpan(0, 0, timeoutSeconds); 153 var response = await client.DeleteAsync(url); 154 //确保HTTP成功状态值 155 response.EnsureSuccessStatusCode(); 156 //await异步读取最后的JSON 157 await response.Content.ReadAsStringAsync().ContinueWith(t => 158 { 159 if (t.IsCompleted) 160 { 161 requestResult.IsSuccess = true; 162 requestResult.Result = t.Result; 163 callback?.Invoke(requestResult); 164 } 165 }); 166 } 167 } 168 catch (Exception e) 169 { 170 if (e.InnerException != null) 171 requestResult.Message = e.InnerException.Message; 172 else if (e.Message.Contains("已取消一个任务")) 173 requestResult.Message = "连接服务器超时，请重试"; 174 else if (e.Message.Contains("404")) 175 requestResult.Message = "连接服务器404，请重试"; 176 else 177 requestResult.Message = e.Message; 178 callback?.Invoke(requestResult); 179 } 180 }
定义一个异步返回信息的类：
1 public class RequestResult : IDisposable 2 { 3 public bool IsSuccess { get; set; } 4 5 public string Result { get; set; } 6 7 public string Message { get; set; } 8 9 public RequestResult(bool isSuccess = false, string result = "", string message = "") 10 { 11 IsSuccess = isSuccess; 12 Result = result; 13 Message = message; 14 } 15 16 ~RequestResult() 17 { 18 Dispose(); 19 } 20 21 public void Dispose() 22 { 23 Dispose(true); 24 GC.SuppressFinalize(this);//不需要再调用本对象的Finalize方法 25 } 26 27 protected virtual void Dispose(Boolean disposing) 28 { 29 if (disposing) 30 { 31 //--- 清理托管资源 ---// 32 } 33 34 //--- 清理非托管资源 ---// 35 } 36 }
附带一个检测网络连接状态的方法：
1 [DllImport("winInet.dll")] 2 private static extern bool InternetGetConnectedState(ref int dwFlag, int dwReserved); 3 4 /// <summary> 5 /// 用于检查网络是否可以连接互联网,true表示连接成功,false表示连接失败 6 /// </summary> 7 /// <returns></returns> 8 private static bool IsConnectedInternet() 9 { 10 int description = 0; 11 return InternetGetConnectedState(ref description, 0); 12 }
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