webapi下的web请求

先看webapi提供的服务：

       [HttpPost]
        public ResultBaseModel SiteList(SiteModel param)
        {
            ResultBaseModel resultModel = new ResultBaseModel();

            var sites = new List<Site>();


            sites.Add(new Site { SiteId = 1, Title = "百度", Uri = "www.baidu.com" });
            sites.Add(new Site { SiteId = 2, Title = "博客园首页", Uri = "www.cnblogs.com" });
            sites.Add(new Site { SiteId = 3, Title = "博问", Uri = "q.cnblogs.com" });
            sites.Add(new Site { SiteId = 4, Title = "新闻", Uri = "news.cnblogs.com" });
            sites.Add(new Site { SiteId = 5, Title = "招聘", Uri = "job.cnblogs.com" });

            try
            {

                var result = (from Site site in sites
                              where site.SiteId > param.StartId
                              select site)
                                .Take(param.ItemCount)
                                .ToList();
                resultModel.IsSuccess = true;
                resultModel.Data = sites;


            }
            catch (Exception ex)
            {
                resultModel.IsSuccess = false;
                resultModel.Message = ex.Message;
            }

            return resultModel;
        }

客户端调用：

   var requestJson = JsonConvert.SerializeObject(new { StartId = 1, ItemCount = 3 });

            var url = "http://localhost:8084/api/CenterShedule/SiteList";
            var responseJson = GetResponseWithNoContentPress(requestJson, url);
            Console.WriteLine(responseJson);

通用的post方法：

        public static string GetResponseWithNoContentPress(string objStr, string url)
        {
            string result = "";
            StreamReader reader = null;
            System.IO.Stream stream = null;
            WebResponse response = null;
            HttpWebRequest request = null;

            try
            {
                byte[] byteArray = Encoding.UTF8.GetBytes(objStr);
                request = (HttpWebRequest)WebRequest.Create(url);
                request.ContentType = "application/json; charset=urf-8";
                request.Accept = "application/json";
                request.ContentLength = byteArray.Length;
                request.KeepAlive = false;
                request.Method = "POST";
                request.Timeout = 600000;
                System.IO.Stream dataStream = request.GetRequestStream();
                dataStream.Write(byteArray, 0, byteArray.Length);
                dataStream.Close();
                response = request.GetResponse();
                stream = response.GetResponseStream();
                reader = new System.IO.StreamReader(stream, Encoding.UTF8);

                result = reader.ReadToEnd();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                if (reader != null)
                {
                    reader.Close();
                }
                if (stream != null)
                {
                    stream.Close();
                }
                if (response != null)
                {
                    response.Close();
                }
                if (request != null)
                {
                    request.Abort();
                    request = null;
                }
            }
            return result;
        }

request.Accept = "application/json"; 这一句可以不用指定返回的类型，webapi自动返回json数据，可是我要返回xml数据怎么办？直接改：request.Accept = "application/xml";这时候请求会报错，报出服务器500错误。于是我改接口：

       [HttpPost]
        public string SiteList(SiteModel param)
        {
            return "hello world";
        }

此时返回来的结果如下：

此时，我就想为什么之前的接口，返回不了数据呢？想了下应该是返回的model无法序列化成xml格式，如何让系统帮助生成xml，使用了各种办法，还是返回服务器500错误，最后决定还是自己写个序列化的方法。在此先不提。

post请求还有一种简洁的写法：

          var requestJson = JsonConvert.SerializeObject(new { StartId = 1, ItemCount = 3 });

            HttpContent httpContent = new StringContent(requestJson);
            httpContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");

            var httpClient = new HttpClient();

            var responseJson = httpClient.PostAsync("http://localhost:8084/api/CenterShedule/SiteList", httpContent)
                .Result.Content.ReadAsStringAsync().Result;

 顺便把get请求的总结下：

 /// <summary>
        /// get请求，可以对请求头进行多项设置
        /// </summary>
        /// <param name="paramArray"></param>
        /// <param name="url"></param>
        /// <returns></returns>
        public static string GetResponseByGetFull(Dictionary<string, string> paramArray, string url)
        {
            string responseJson = "";

            var httpclient = HTTPHelper.HttpClient;

            url += BuildParam(paramArray);
            var response = httpclient.GetAsync(url).Result;
            if (response.IsSuccessStatusCode)
            {
                Stream myResponseStream = response.Content.ReadAsStreamAsync().Result;
                StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
                responseJson = myStreamReader.ReadToEnd();
                myStreamReader.Close();
                myResponseStream.Close();
            }

            return responseJson;
        }

HttpClient：

   public class HTTPHelper
    {
        private static readonly HttpClient HttpClient;
        static HTTPHelper()
        {
            var handler = new HttpClientHandler() { AutomaticDecompression = DecompressionMethods.None };
            HttpClient = new HttpClient(handler);

            HttpClient.DefaultRequestHeaders.Accept.Clear();
            HttpClient.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
        }

BuildParam：

       private static string BuildParam(Dictionary<string, string> paramArray)
        {
            string url = "";
            if (paramArray != null && paramArray.Count > 0)
            {
                var parms = "";
                foreach (var item in paramArray)
                {
                    parms += string.Format("{0}={1}&", item.Key, item.Value);
                }
                if (parms != "")
                {
                    parms = "?" + parms.TrimEnd('&');
                }
                url += parms;

            }
            return url;
        }