一. 前言
前端调用有Form表单提交,ajax提交,ajax一般是用Jquery的简化写法,在这里不再过多介绍; 后端调用大约有这些:WebCient、WebRequest、Httpclient、WebapiClient,重点探讨Get和Post请求,Put和Delete请求用较少。
下面排着介绍Get和Post的基本写法,最后再封装一下,便于调用。
PS:其中Post请求有两种,分别是: "application/x-www-form-urlencoded"表单提交的方式 和 "application/json" Json格式提交的方式。
(1). Post的表单提交的格式为:"userName=admin&pwd=123456"。
(2). Post的Json的提交格式为:将实体(类)转换成json字符串。
下面先编写几个服务器端的接口方法,便于调用。
1 //Get http://localhost:2131/api/Forth/CheckLogin?userName=admin&pwd=123456 2 [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 }
为了方便下面的测试,给上述三个地址进行命名描述和序列化方法的初始化
二. WebClient
1. Get请求
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的表单提交方式(url2能访问,url3报500错误)
1 WebClient wc = new WebClient(); 2 string url = url3; 3 wc.Encoding = Encoding.UTF8; 4 //也可以向表头中添加一些其他东西 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都能正常访问)
1 var user = new 2 { 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();
三. WebRequest
1. Get请求
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的表单提交方式(url2能访问,url3报500错误)
1 var postData = "userName=admin&pwd=123456"; 2 var request = HttpWebRequest.Create(url2) as HttpWebRequest; 3 request.Timeout = 30 * 1000;//设置30s的超时 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都能正常访问)
1 var user = new 2 { 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; //设置30s的超时 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();
四. HttpClient
1. Get请求
1 var handler = new HttpClientHandler(); 2 using (var http = new HttpClient(handler)) 3 { 4 var response = http.GetAsync(url1).Result; 5 //获取Http的状态值 6 //Console.WriteLine(response.StatusCode); 7 string result = response.Content.ReadAsStringAsync().Result; 8 Console.WriteLine(result); 9 Console.ReadKey(); 10 }
2. Post的表单提交方式(url2能访问,url3报500错误)
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 //获取Http的状态值 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都能正常访问)
1 var user = new 2 { 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 //获取Http的状态值 12 //Console.WriteLine(response.StatusCode); 13 string result = response.Content.ReadAsStringAsync().Result; 14 Console.WriteLine(result); 15 Console.ReadKey(); 16 }
注:以上代码均是官方的给出的标准写法,但存在很严重的问题,当请求量大的时候,会存在不能释放的问题,解决方案见下面。
解决方案:
将HttpClient做成单例的,不用Using,全局只有一个,来解决tcp连接不能释放的问题。
1 /// <summary> 2 /// 将HttpClient做成单例的,不用Using,全局只有一个 3 /// 来解决tcp连接不能释放的问题 4 /// </summary> 5 public class HttpClientFactory 6 { 7 private static HttpClient _httpClient = null; 8 9 /// <summary> 10 /// 静态的构造函数:只能有一个,且是无参数的 11 /// 由CLR保证,只有在程序第一次使用该类之前被调用,而且只能调用一次 12 /// 说明: keep-alive关键字可以理解为一个长链接,超时时间也可以在上面进行设置,例如10秒的超时时间,当然并发量太大,这个10秒应该会抛弃很多请求 13 /// 发送请求的代码没有了using,即这个httpclient不会被手动dispose,而是由系统控制它,当然你的程序重启时,这也就被回收了。 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 /// 对外开放接口 24 /// </summary> 25 /// <returns></returns> 26 public static HttpClient GetHttpClient() 27 { 28 return _httpClient; 29 } 30 }
优化后调用进行Get和Post请求,代码如下
1 var http = HttpClientFactory.GetHttpClient(); 2 //1.Get请求 3 var response1 = http.GetAsync(url1).Result; 4 var result1 = response1.Content.ReadAsStringAsync().Result; 5 Console.WriteLine($"Get请求的返回值为:{result1}"); 6 //2. Post请求【application/x-www-form-urlencoded】 7 var content2 = new StringContent("userName=admin&pwd=123456", Encoding.UTF8, "application/x-www-form-urlencoded"); 8 var response2 = http.PostAsync(url2, content2).Result; 9 string result2 = response2.Content.ReadAsStringAsync().Result; 10 Console.WriteLine($"Post请求【application/x-www-form-urlencoded】的返回值为:{result2}"); 11 //3. Post请求 【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请求【application/json】的返回值为:{result3}"); 21 Console.ReadKey();
五. 扩展
将WebClient、WebRequest、HttpClient三个类进行封装,其中HttpClient做成单例的,便于我们调用。
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 /// <summary> 2 /// 总结各种请求方式 3 /// </summary> 4 public static class RequestWaysHelp 5 { 6 #region 01-WebClient的Get请求 7 /// <summary> 8 /// WebClient的Get请求 9 /// </summary> 10 /// <param name="url">请求地址,含拼接数据,请求格式为:"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 #endregion 19 20 #region 02-WebClient的Post请求 21 /// <summary> 22 /// WebClient的Post请求 23 /// 表单提交模式[application/x-www-form-urlencoded] 24 /// </summary> 25 /// <param name="url">请求地址,单纯的地址,没有数据拼接</param> 26 /// <param name="data">请求数据,格式为:"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 //也可以向表头中添加一些其他东西 33 wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded"); 34 return wc.UploadString(url, data); 35 } 36 #endregion 37 38 #region 03-WebClient的Post请求 39 /// <summary> 40 /// WebClient的Post请求 41 /// Json提交模式[application/json] 42 /// </summary> 43 /// <param name="url">请求地址,单纯的地址,没有数据拼接</param> 44 /// <param name="data">请求数据,格式为(Json)对象、或者类对象 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 //也可以向表头中添加一些其他东西 53 wc.Headers.Add("Content-Type", "application/json"); 54 return wc.UploadString(url, jss.Serialize(data)); 55 } 56 #endregion 57 58 #region 04-HttpWebRequest的Get请求 59 /// <summary> 60 /// HttpWebRequest的Get请求 61 /// </summary> 62 /// <param name="url">请求地址,含拼接数据,请求格式为:"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 #endregion 82 83 #region 05-HttpWebRequest的Post请求 84 /// <summary> 85 /// HttpWebRequest的Post请求 86 /// 表单提交模式[application/x-www-form-urlencoded] 87 /// </summary> 88 /// <param name="url">请求地址,单纯的地址,没有数据拼接</param> 89 /// <param name="data">请求数据,格式为:"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;//设置30s的超时 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请求 117 /// <summary> 118 /// HttpWebRequest的Post请求 119 /// Json提交模式[application/json] 120 /// </summary> 121 /// <param name="url">请求地址,单纯的地址,没有数据拼接</param> 122 /// <param name="data">请求数据,格式为(Json)对象、或者类对象 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; //设置30s的超时 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请求 152 /// <summary> 153 /// HttpClient的Get请求 154 /// </summary> 155 ///<param name="url">请求地址,含拼接数据,请求格式为:"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请求 166 /// <summary> 167 /// HttpClient的Post请求 168 /// 表单提交模式[application/x-www-form-urlencoded] 169 /// </summary> 170 /// <param name="url">请求地址,单纯的地址,没有数据拼接</param> 171 /// <param name="data">请求数据,格式为:"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请求 183 /// <summary> 184 /// HttpClient的Post请求 185 /// Json提交模式[application/json] 186 /// </summary> 187 /// <param name="url">请求地址,单纯的地址,没有数据拼接</param> 188 /// <param name="data">请求数据,格式为(Json)对象、或者类对象 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 /// 将HttpClient做成单例的,不用Using,全局只有一个 205 /// 来解决tcp连接不能释放的问题 206 /// </summary> 207 public class HttpClientFactory2 208 { 209 private static HttpClient _httpClient = null; 210 211 /// <summary> 212 /// 静态的构造函数:只能有一个,且是无参数的 213 /// 由CLR保证,只有在程序第一次使用该类之前被调用,而且只能调用一次 214 /// 说明: keep-alive关键字可以理解为一个长链接,超时时间也可以在上面进行设置,例如10秒的超时时间,当然并发量太大,这个10秒应该会抛弃很多请求 215 /// 发送请求的代码没有了using,即这个httpclient不会被手动dispose,而是由系统控制它,当然你的程序重启时,这也就被回收了。 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 /// 对外开放接口 226 /// </summary> 227 /// <returns></returns> 228 public static HttpClient GetHttpClient() 229 { 230 return _httpClient; 231 } 232 }
封装后的调用:
1 var user = new 2 { 3 userName = "admin", 4 pwd = "123456" 5 }; 6 // WebClient的相关测试 7 { 8 Console.WriteLine("1.WebClient的相关测试"); 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的相关测试 17 { 18 Console.WriteLine("2.HttpWebRequest的相关测试"); 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的相关测试 27 { 28 Console.WriteLine("3.HttpClient的相关测试"); 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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- 作 者 : Yaopengfei(姚鹏飞)
- 博客地址 : http://www.cnblogs.com/yaopengfei/
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