一. 前言

　　前端調(diào)用有Form表單提交，ajax提交，ajax一般是用Jquery的簡(jiǎn)化寫法，在這里不再過多介紹；?后端調(diào)用大約有這些：WebCient、WebRequest、Httpclient、WebapiClient，重點(diǎn)探討Get和Post請(qǐng)求，Put和Delete請(qǐng)求用較少。

下面排著介紹Get和Post的基本寫法，最后再封裝一下，便于調(diào)用。

PS：其中Post請(qǐng)求有兩種，分別是： "application/x-www-form-urlencoded"表單提交的方式 和 "application/json" Json格式提交的方式。

(1). Post的表單提交的格式為："userName=admin&pwd=123456"。

(2). Post的Json的提交格式為：將實(shí)體(類)轉(zhuǎn)換成json字符串。

下面先編寫幾個(gè)服務(wù)器端的接口方法，便于調(diào)用。

1 //Get http://localhost:2131/api/Forth/CheckLogin?userName=admin&pwd=1234562 [HttpGet]3 public string CheckLogin(string userName, string pwd)4 {5 if (userName == "admin" && pwd == "123456")6 {7 return "ok";8 }9 else 10 { 11 return "error"; 12 } 13 } 14 15 16 //Post http://localhost:2131/api/Forth/Register 17 [HttpPost] 18 public string Register([FromBody]LoginModel model) 19 { 20 if (model.userName == "admin" && model.pwd == "123456") 21 { 22 return "ok"; 23 } 24 else 25 { 26 return "error"; 27 } 28 } 29 30 //Post http://localhost:2131/api/Forth/Register2 31 [HttpPost] 32 public string Register2([FromBody]dynamic model) 33 { 34 if (model.userName == "admin" && model.pwd == "123456") 35 { 36 return "ok"; 37 } 38 else 39 { 40 return "error"; 41 } 42 }

為了方便下面的測(cè)試，給上述三個(gè)地址進(jìn)行命名描述和序列化方法的初始化

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二. WebClient

?1. Get請(qǐng)求

1 WebClient wc = new WebClient(); 2 string url = url1; 3 wc.Encoding = Encoding.UTF8; 4 string result = wc.DownloadString(url); 5 Console.WriteLine(result); 6 Console.ReadKey();

2. Post的表單提交方式（url2能訪問，url3報(bào)500錯(cuò)誤）

1 WebClient wc = new WebClient(); 2 string url = url3; 3 wc.Encoding = Encoding.UTF8; 4 //也可以向表頭中添加一些其他東西 5 wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded"); 6 string result = wc.UploadString(url, "userName=admin&pwd=123456"); 7 Console.WriteLine(result); 8 Console.ReadKey();

3. Post的JSON提交格式(url2和url3都能正常訪問)

1 var user = new2 {3 userName = "admin",4 pwd = "123456"5 };6 WebClient wc = new WebClient();7 string url = url3;8 wc.Encoding = Encoding.UTF8;9 wc.Headers.Add("Content-Type", "application/json"); 10 string result = wc.UploadString(url, jss.Serialize(user)); 11 Console.WriteLine(result); 12 Console.ReadKey();

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三. WebRequest

1. Get請(qǐng)求

1 HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url1);2 request.Timeout = 30 * 1000;3 request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.118 Safari/537.36";4 request.ContentType = "application/x-www-form-urlencoded; charset=UTF-8";5 string result = "";6 using (var res = request.GetResponse() as HttpWebResponse)7 {8 if (res.StatusCode == HttpStatusCode.OK)9 { 10 StreamReader reader = new StreamReader(res.GetResponseStream(), Encoding.UTF8); 11 result = reader.ReadToEnd(); 12 } 13 } 14 Console.WriteLine(result); 15 Console.ReadKey();

2. Post的表單提交方式（url2能訪問，url3報(bào)500錯(cuò)誤）

1 var postData = "userName=admin&pwd=123456";2 var request = HttpWebRequest.Create(url2) as HttpWebRequest;3 request.Timeout = 30 * 1000;//設(shè)置30s的超時(shí)4 request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.118 Safari/537.36";5 request.ContentType = "application/x-www-form-urlencoded";6 request.Method = "POST";7 byte[] data = Encoding.UTF8.GetBytes(postData);8 request.ContentLength = data.Length;9 Stream postStream = request.GetRequestStream(); 10 postStream.Write(data, 0, data.Length); 11 postStream.Close(); 12 string result = ""; 13 using (var res = request.GetResponse() as HttpWebResponse) 14 { 15 if (res.StatusCode == HttpStatusCode.OK) 16 { 17 StreamReader reader = new StreamReader(res.GetResponseStream(), Encoding.UTF8); 18 result = reader.ReadToEnd(); 19 } 20 } 21 Console.WriteLine(result); 22 Console.ReadKey();

3. Post的JSON提交格式(url2和url3都能正常訪問)

1 var user = new2 {3 userName = "admin",4 pwd = "123456"5 };6 var postData = jss.Serialize(user);7 var request = HttpWebRequest.Create(url2) as HttpWebRequest;8 request.Timeout = 30 * 1000; //設(shè)置30s的超時(shí)9 request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.118 Safari/537.36"; 10 request.ContentType = "application/json"; 11 request.Method = "POST"; 12 byte[] data = Encoding.UTF8.GetBytes(postData); 13 request.ContentLength = data.Length; 14 Stream postStream = request.GetRequestStream(); 15 postStream.Write(data, 0, data.Length); 16 postStream.Close(); 17 string result = ""; 18 using (var res = request.GetResponse() as HttpWebResponse) 19 { 20 if (res.StatusCode == HttpStatusCode.OK) 21 { 22 StreamReader reader = new StreamReader(res.GetResponseStream(), Encoding.UTF8); 23 result = reader.ReadToEnd(); 24 } 25 } 26 Console.WriteLine(result); 27 Console.ReadKey();

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四. HttpClient

1. Get請(qǐng)求

1 　　　　　　　　var handler = new HttpClientHandler();2 using (var http = new HttpClient(handler))3 {4 var response = http.GetAsync(url1).Result;5 //獲取Http的狀態(tài)值6 //Console.WriteLine(response.StatusCode);7 string result = response.Content.ReadAsStringAsync().Result;8 Console.WriteLine(result);9 Console.ReadKey(); 10 }

2. Post的表單提交方式（url2能訪問，url3報(bào)500錯(cuò)誤）

1 var handler = new HttpClientHandler();2 using (var http = new HttpClient(handler))3 {4 var content = new StringContent("userName=admin&pwd=123456", Encoding.UTF8, "application/x-www-form-urlencoded");5 var response = http.PostAsync(url2, content).Result;6 //獲取Http的狀態(tài)值7 //Console.WriteLine(response.StatusCode);8 string result = response.Content.ReadAsStringAsync().Result;9 Console.WriteLine(result); 10 Console.ReadKey(); 11 }

3. Post的JSON提交格式(url2和url3都能正常訪問)

1 　　　　　　　　var user = new2 {3 userName = "admin",4 pwd = "123456"5 };6 var handler = new HttpClientHandler();7 using (var http = new HttpClient(handler))8 {9 var content = new StringContent(jss.Serialize(user), Encoding.UTF8, "application/json"); 10 var response = http.PostAsync(url3, content).Result; 11 //獲取Http的狀態(tài)值 12 //Console.WriteLine(response.StatusCode); 13 string result = response.Content.ReadAsStringAsync().Result; 14 Console.WriteLine(result); 15 Console.ReadKey(); 16 }

注：以上代碼均是官方的給出的標(biāo)準(zhǔn)寫法，但存在很嚴(yán)重的問題，當(dāng)請(qǐng)求量大的時(shí)候，會(huì)存在不能釋放的問題，解決方案見下面。

解決方案：

　　將HttpClient做成單例的，不用Using，全局只有一個(gè)，來解決tcp連接不能釋放的問題。

1 /// <summary>2 /// 將HttpClient做成單例的，不用Using，全局只有一個(gè)3 /// 來解決tcp連接不能釋放的問題4 /// </summary>5 public class HttpClientFactory6 {7 private static HttpClient _httpClient = null;8 9 /// <summary> 10 /// 靜態(tài)的構(gòu)造函數(shù)：只能有一個(gè)，且是無參數(shù)的 11 /// 由CLR保證，只有在程序第一次使用該類之前被調(diào)用，而且只能調(diào)用一次 12 /// 說明： keep-alive關(guān)鍵字可以理解為一個(gè)長(zhǎng)鏈接，超時(shí)時(shí)間也可以在上面進(jìn)行設(shè)置，例如10秒的超時(shí)時(shí)間，當(dāng)然并發(fā)量太大，這個(gè)10秒應(yīng)該會(huì)拋棄很多請(qǐng)求 13 /// 發(fā)送請(qǐng)求的代碼沒有了using，即這個(gè)httpclient不會(huì)被手動(dòng)dispose，而是由系統(tǒng)控制它，當(dāng)然你的程序重啟時(shí)，這也就被回收了。 14 /// </summary> 15 static HttpClientFactory() 16 { 17 _httpClient = new HttpClient(new HttpClientHandler()); 18 _httpClient.Timeout = new TimeSpan(0, 0, 10); 19 _httpClient.DefaultRequestHeaders.Connection.Add("keep-alive"); 20 } 21 22 /// <summary> 23 /// 對(duì)外開放接口 24 /// </summary> 25 /// <returns></returns> 26 public static HttpClient GetHttpClient() 27 { 28 return _httpClient; 29 } 30 }

優(yōu)化后調(diào)用進(jìn)行Get和Post請(qǐng)求，代碼如下

1 　　　　　　　　var http = HttpClientFactory.GetHttpClient();2 //1.Get請(qǐng)求3 var response1 = http.GetAsync(url1).Result;4 var result1 = response1.Content.ReadAsStringAsync().Result;5 Console.WriteLine($"Get請(qǐng)求的返回值為：{result1}");6 //2. Post請(qǐng)求【application/x-www-form-urlencoded】7 var content2 = new StringContent("userName=admin&pwd=123456", Encoding.UTF8, "application/x-www-form-urlencoded");8 var response2 = http.PostAsync(url2, content2).Result;9 string result2 = response2.Content.ReadAsStringAsync().Result; 10 Console.WriteLine($"Post請(qǐng)求【application/x-www-form-urlencoded】的返回值為：{result2}"); 11 //3. Post請(qǐng)求 【application/json】 12 var user = new 13 { 14 userName = "admin", 15 pwd = "123456" 16 }; 17 var content3 = new StringContent(jss.Serialize(user), Encoding.UTF8, "application/json"); 18 var response3 = http.PostAsync(url3, content3).Result; 19 string result3 = response3.Content.ReadAsStringAsync().Result; 20 Console.WriteLine($"Post請(qǐng)求【application/json】的返回值為：{result3}"); 21 Console.ReadKey();

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五. 擴(kuò)展

?　　將WebClient、WebRequest、HttpClient三個(gè)類進(jìn)行封裝，其中HttpClient做成單例的，便于我們調(diào)用。

1 /// <summary>2 /// 總結(jié)各種請(qǐng)求方式3 /// </summary>4 public static class RequestWaysHelp5 {6 #region 01-WebClient的Get請(qǐng)求7 /// <summary>8 /// WebClient的Get請(qǐng)求9 /// </summary>10 /// <param name="url">請(qǐng)求地址,含拼接數(shù)據(jù)，請(qǐng)求格式為："http://XXXX?userName=admin&pwd=123456";</param>11 /// <returns></returns>12 public static string WcGet(string url)13 {14 WebClient wc = new WebClient();15 wc.Encoding = Encoding.UTF8;16 return wc.DownloadString(url);17 }18 #endregion19 20 #region 02-WebClient的Post請(qǐng)求21 /// <summary>22 /// WebClient的Post請(qǐng)求23 /// 表單提交模式[application/x-www-form-urlencoded]24 /// </summary>25 /// <param name="url">請(qǐng)求地址,單純的地址,沒有數(shù)據(jù)拼接</param>26 /// <param name="data">請(qǐng)求數(shù)據(jù),格式為:"userName=admin&pwd=123456"</param>27 /// <returns></returns>28 public static string WcPost1(string url, string data)29 {30 WebClient wc = new WebClient();31 wc.Encoding = Encoding.UTF8;32 //也可以向表頭中添加一些其他東西33 wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded");34 return wc.UploadString(url, data);35 }36 #endregion37 38 #region 03-WebClient的Post請(qǐng)求39 /// <summary>40 /// WebClient的Post請(qǐng)求41 /// Json提交模式[application/json]42 /// </summary>43 /// <param name="url">請(qǐng)求地址,單純的地址,沒有數(shù)據(jù)拼接</param>44 /// <param name="data">請(qǐng)求數(shù)據(jù),格式為(Json)對(duì)象、或者類對(duì)象 eg： new {id="1"}</param>45 /// <returns></returns>46 public static string WcPost2(string url, object data)47 {48 JavaScriptSerializer jss = new JavaScriptSerializer();49 50 WebClient wc = new WebClient();51 wc.Encoding = Encoding.UTF8;52 //也可以向表頭中添加一些其他東西53 wc.Headers.Add("Content-Type", "application/json");54 return wc.UploadString(url, jss.Serialize(data));55 }56 #endregion57 58 #region 04-HttpWebRequest的Get請(qǐng)求59 /// <summary>60 /// HttpWebRequest的Get請(qǐng)求61 /// </summary>62 /// <param name="url">請(qǐng)求地址,含拼接數(shù)據(jù)，請(qǐng)求格式為："http://XXXX?userName=admin&pwd=123456";</param>63 /// <returns></returns>64 public static string HwGet(string url)65 {66 HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);67 request.Timeout = 30 * 1000;68 request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.118 Safari/537.36";69 request.ContentType = "application/x-www-form-urlencoded; charset=UTF-8";70 string result = "";71 using (var res = request.GetResponse() as HttpWebResponse)72 {73 if (res.StatusCode == HttpStatusCode.OK)74 {75 StreamReader reader = new StreamReader(res.GetResponseStream(), Encoding.UTF8);76 result = reader.ReadToEnd();77 }78 }79 return result;80 }81 #endregion82 83 #region 05-HttpWebRequest的Post請(qǐng)求84 /// <summary>85 /// HttpWebRequest的Post請(qǐng)求86 /// 表單提交模式[application/x-www-form-urlencoded]87 /// </summary>88 /// <param name="url">請(qǐng)求地址,單純的地址,沒有數(shù)據(jù)拼接</param>89 /// <param name="data">請(qǐng)求數(shù)據(jù),格式為:"userName=admin&pwd=123456"</param>90 /// <returns></returns>91 public static string HwPost1(string url, string data)92 {93 var request = HttpWebRequest.Create(url) as HttpWebRequest;94 request.Timeout = 30 * 1000;//設(shè)置30s的超時(shí)95 request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.118 Safari/537.36";96 request.ContentType = "application/x-www-form-urlencoded";97 request.Method = "POST";98 byte[] data2 = Encoding.UTF8.GetBytes(data);99 request.ContentLength = data2.Length; 100 Stream postStream = request.GetRequestStream(); 101 postStream.Write(data2, 0, data2.Length); 102 postStream.Close(); 103 string result = ""; 104 using (var res = request.GetResponse() as HttpWebResponse) 105 { 106 if (res.StatusCode == HttpStatusCode.OK) 107 { 108 StreamReader reader = new StreamReader(res.GetResponseStream(), Encoding.UTF8); 109 result = reader.ReadToEnd(); 110 } 111 } 112 return result; 113 } 114 #endregion 115 116 #region 06-HttpWebRequest的Post請(qǐng)求 117 /// <summary> 118 /// HttpWebRequest的Post請(qǐng)求 119 /// Json提交模式[application/json] 120 /// </summary> 121 /// <param name="url">請(qǐng)求地址,單純的地址,沒有數(shù)據(jù)拼接</param> 122 /// <param name="data">請(qǐng)求數(shù)據(jù),格式為(Json)對(duì)象、或者類對(duì)象 eg： new {id="1"}</param> 123 /// <returns></returns> 124 public static string HwPost2(string url, object data) 125 { 126 JavaScriptSerializer jss = new JavaScriptSerializer(); 127 var postData = jss.Serialize(data); 128 var request = HttpWebRequest.Create(url) as HttpWebRequest; 129 request.Timeout = 30 * 1000; //設(shè)置30s的超時(shí) 130 request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.118 Safari/537.36"; 131 request.ContentType = "application/json"; 132 request.Method = "POST"; 133 byte[] data2 = Encoding.UTF8.GetBytes(postData); 134 request.ContentLength = data2.Length; 135 Stream postStream = request.GetRequestStream(); 136 postStream.Write(data2, 0, data2.Length); 137 postStream.Close(); 138 string result = ""; 139 using (var res = request.GetResponse() as HttpWebResponse) 140 { 141 if (res.StatusCode == HttpStatusCode.OK) 142 { 143 StreamReader reader = new StreamReader(res.GetResponseStream(), Encoding.UTF8); 144 result = reader.ReadToEnd(); 145 } 146 } 147 return result; 148 } 149 #endregion 150 151 #region 07-HttpClient的Get請(qǐng)求 152 /// <summary> 153 /// HttpClient的Get請(qǐng)求 154 /// </summary> 155 ///<param name="url">請(qǐng)求地址,含拼接數(shù)據(jù)，請(qǐng)求格式為："http://XXXX?userName=admin&pwd=123456";</param> 156 /// <returns></returns> 157 public static string HcGet(string url) 158 { 159 var http = HttpClientFactory2.GetHttpClient(); 160 var response1 = http.GetAsync(url).Result; 161 return response1.Content.ReadAsStringAsync().Result; 162 } 163 #endregion 164 165 #region 08-HttpClient的Post請(qǐng)求 166 /// <summary> 167 /// HttpClient的Post請(qǐng)求 168 /// 表單提交模式[application/x-www-form-urlencoded] 169 /// </summary> 170 /// <param name="url">請(qǐng)求地址,單純的地址,沒有數(shù)據(jù)拼接</param> 171 /// <param name="data">請(qǐng)求數(shù)據(jù),格式為:"userName=admin&pwd=123456"</param> 172 /// <returns></returns> 173 public static string HcPost1(string url, string data) 174 { 175 var http = HttpClientFactory2.GetHttpClient(); 176 var content = new StringContent(data, Encoding.UTF8, "application/x-www-form-urlencoded"); 177 var response = http.PostAsync(url, content).Result; 178 return response.Content.ReadAsStringAsync().Result; 179 } 180 #endregion 181 182 #region 09-HttpClient的Post請(qǐng)求 183 /// <summary> 184 /// HttpClient的Post請(qǐng)求 185 /// Json提交模式[application/json] 186 /// </summary> 187 /// <param name="url">請(qǐng)求地址,單純的地址,沒有數(shù)據(jù)拼接</param> 188 /// <param name="data">請(qǐng)求數(shù)據(jù),格式為(Json)對(duì)象、或者類對(duì)象 eg： new {id="1"}</param> 189 /// <returns></returns> 190 public static string HcPost2(string url, object data) 191 { 192 JavaScriptSerializer jss = new JavaScriptSerializer(); 193 var http = HttpClientFactory2.GetHttpClient(); 194 var content = new StringContent(jss.Serialize(data), Encoding.UTF8, "application/json"); 195 var response = http.PostAsync(url, content).Result; 196 return response.Content.ReadAsStringAsync().Result; 197 } 198 #endregion 199 200 201 } 202 203 /// <summary> 204 /// 將HttpClient做成單例的，不用Using，全局只有一個(gè) 205 /// 來解決tcp連接不能釋放的問題 206 /// </summary> 207 public class HttpClientFactory2 208 { 209 private static HttpClient _httpClient = null; 210 211 /// <summary> 212 /// 靜態(tài)的構(gòu)造函數(shù)：只能有一個(gè)，且是無參數(shù)的 213 /// 由CLR保證，只有在程序第一次使用該類之前被調(diào)用，而且只能調(diào)用一次 214 /// 說明： keep-alive關(guān)鍵字可以理解為一個(gè)長(zhǎng)鏈接，超時(shí)時(shí)間也可以在上面進(jìn)行設(shè)置，例如10秒的超時(shí)時(shí)間，當(dāng)然并發(fā)量太大，這個(gè)10秒應(yīng)該會(huì)拋棄很多請(qǐng)求 215 /// 發(fā)送請(qǐng)求的代碼沒有了using，即這個(gè)httpclient不會(huì)被手動(dòng)dispose，而是由系統(tǒng)控制它，當(dāng)然你的程序重啟時(shí)，這也就被回收了。 216 /// </summary> 217 static HttpClientFactory2() 218 { 219 _httpClient = new HttpClient(new HttpClientHandler()); 220 _httpClient.Timeout = new TimeSpan(0, 0, 10); 221 _httpClient.DefaultRequestHeaders.Connection.Add("keep-alive"); 222 } 223 224 /// <summary> 225 /// 對(duì)外開放接口 226 /// </summary> 227 /// <returns></returns> 228 public static HttpClient GetHttpClient() 229 { 230 return _httpClient; 231 } 232 }

封裝后的調(diào)用：

1 　　　　　　　　 var user = new2 {3 userName = "admin",4 pwd = "123456"5 };6 // WebClient的相關(guān)測(cè)試7 {8 Console.WriteLine("1.WebClient的相關(guān)測(cè)試");9 var result1 = RequestWaysHelp.WcGet(url1); 10 Console.WriteLine(result1); 11 var result2 = RequestWaysHelp.WcPost1(url2, "userName=admin&pwd=123456"); 12 Console.WriteLine(result2); 13 var result3 = RequestWaysHelp.WcPost2(url3, user); 14 Console.WriteLine(result3); 15 } 16 // HttpWebRequest的相關(guān)測(cè)試 17 { 18 Console.WriteLine("2.HttpWebRequest的相關(guān)測(cè)試"); 19 var result1 = RequestWaysHelp.HwGet(url1); 20 Console.WriteLine(result1); 21 var result2 = RequestWaysHelp.HwPost1(url2, "userName=admin&pwd=123456"); 22 Console.WriteLine(result2); 23 var result3 = RequestWaysHelp.HwPost2(url3, user); 24 Console.WriteLine(result3); 25 } 26 // HttpClient的相關(guān)測(cè)試 27 { 28 Console.WriteLine("3.HttpClient的相關(guān)測(cè)試"); 29 var result1 = RequestWaysHelp.HcGet(url1); 30 Console.WriteLine(result1); 31 var result2 = RequestWaysHelp.HcPost1(url2, "userName=admin&pwd=123456"); 32 Console.WriteLine(result2); 33 var result3 = RequestWaysHelp.HcPost2(url3, user); 34 Console.WriteLine(result3); 35 }

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總結(jié)

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