ASP.NET Web Api 實踐系列（二）Get/Post方式調用Web Api

標籤：

    本文給出Get/Post方式訪問Web Api的協助方法，對於Put/Delete方式的調用跟Post調用類似。

    一、Web Api調用協助類

    下面給出Web Api調用協助類的代碼：

  1 using System;  2 using System.Collections.Generic;  3 using System.Net.Http;  4 using System.Net.Http.Headers;  5 using System.Text;  6 using System.Web;  7   8 namespace TestApi  9 { 10     /// <summary> 11     /// WebApi訪問協助類 12     /// </summary> 13     public class WebApiHepler 14     { 15         /// <summary> 16         /// 產生最終URL 17         /// </summary> 18         /// <param name="baseUrl">基準URL（不含查詢串）</param> 19         /// <param name="dictParam">查詢參數字典</param> 20         /// <returns>最終URL</returns> 21         private static string GetLastUrl(string baseUrl, Dictionary<string, string> dictParam) 22         { 23             var sbUrl = new StringBuilder(baseUrl); 24             if (dictParam != null && dictParam.Count > 0) 25             { 26                 sbUrl.Append("?"); 27                 int index = 0; 28                 foreach (var item in dictParam) 29                 { 30                     sbUrl.Append(string.Format("{0}={1}", item.Key, 31                         HttpUtility.UrlEncode(item.Value, Encoding.UTF8))); 32                     if (index < dictParam.Count - 1) 33                     { 34                         sbUrl.Append("&"); 35                     } 36                     index++; 37                 } 38             } 39             var url = sbUrl.ToString(); 40             return url; 41         } 42  43         /// <summary> 44         /// GET方式調用Web Api 45         /// </summary> 46         /// <param name="baseUrl">基準URL（不含查詢串）</param> 47         /// <param name="dictParam">查詢參數字典</param> 48         /// <param name="result">返回資料（Json格式）</param> 49         /// <param name="errMsg">出錯資訊</param> 50         /// <returns>成功與否</returns> 51         public static bool Get(string baseUrl, Dictionary<string, string> dictParam, out string result, out string errMsg) 52         { 53             errMsg = string.Empty; 54             result = string.Empty; 55             try 56             { 57                 using (var client = new HttpClient()) 58                 { 59                     client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json")); 60                     var url = GetLastUrl(baseUrl, dictParam); 61                     var tmpResult = client.GetAsync(url).Result; 62                     tmpResult.EnsureSuccessStatusCode(); 63                     result = tmpResult.Content.ReadAsStringAsync().Result; 64                     return true; 65                 } 66             } 67             catch (Exception ex) 68             { 69                 errMsg = ex.Message; 70                 return false; 71             } 72              73         } 74  75         /// <summary> 76         /// POST方式調用Web Api 77         /// </summary> 78         /// <param name="baseUrl">基準URL（不含查詢串）</param> 79         /// <param name="dictParam">查詢參數字典</param> 80         /// <param name="parseData">傳遞實體資料（Json格式）</param> 81         /// <param name="result">返回資料（Json格式）</param> 82         /// <param name="errMsg">出錯資訊</param> 83         /// <returns>成功與否</returns> 84         public static bool Post(string baseUrl, Dictionary<string, string> dictParam, string parseData, out string result, out string errMsg) 85         { 86             errMsg = string.Empty; 87             result = string.Empty; 88             try 89             { 90                 using (var client = new HttpClient()) 91                 { 92                     client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json")); 93                     var url = GetLastUrl(baseUrl, dictParam); 94                     var content = new StringContent(parseData, Encoding.UTF8); 95                     content.Headers.ContentType = new MediaTypeHeaderValue("application/json"); 96                     var tmpResult = client.PostAsync(url, content).Result; 97                     tmpResult.EnsureSuccessStatusCode(); 98                     result = tmpResult.Content.ReadAsStringAsync().Result; 99                     return true;100                 }101             }102             catch (Exception ex)103             {104                 errMsg = ex.Message;105                 return false;106             }107         }108     }109 }

    二、部分說明

    對以上的代碼作部分說明：

• GetLastUrl方法用於根據基準URL和查詢參數字典擷取最終URL
• client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));這句代碼錶示希望服務返回Json字串。
• content.Headers.ContentType = new MediaTypeHeaderValue("application/json"); 表示以Json格式傳遞實體內容。

 

ASP.NET Web Api 實踐系列（二）Get/Post方式調用Web Api