C# 調用HTTP接口兩種方式Demo

本Demo大部分參考原著：http://www.jianshu.com/p/cfdaf6857e7e

在WebApi發布之前，我們都是通過WebRequest/WebResponse這兩個類組合來調用HTTP接口的

封裝一個RestClient類

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Web;

namespace WebApplication1
{
    public class RestClient
    {
        private string BaseUri;
        public RestClient(string baseUri)
        {
            this.BaseUri = baseUri;
        }

        #region Get請求
        public string Get(string uri)
        {
            //先根據用戶請求的uri構造請求地址
            string serviceUrl = string.Format("{0}/{1}", this.BaseUri, uri);
            //創建Web訪問對  象
            HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(serviceUrl);
            //通過Web訪問對象獲取響應內容
            HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
            //通過響應內容流創建StreamReader對象，因為StreamReader更高級更快
            StreamReader reader = new StreamReader(myResponse.GetResponseStream(),Encoding.UTF8);
            //string returnXml = HttpUtility.UrlDecode(reader.ReadToEnd());//如果有編碼問題就用這個方法
            string returnXml = reader.ReadToEnd();//利用StreamReader就可以從響應內容從頭讀到尾
            reader.Close();
            myResponse.Close();
            return returnXml;
        }
        #endregion

        #region Post請求
        public string Post(string data, string uri)
        {
            //先根據用戶請求的uri構造請求地址
            string serviceUrl = string.Format("{0}/{1}", this.BaseUri, uri);
            //創建Web訪問對象
            HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(serviceUrl);
            //把用戶傳過來的數據轉成“UTF-8”的字節流
            byte[] buf = System.Text.Encoding.GetEncoding("UTF-8").GetBytes(data);

            myRequest.Method = "POST";
            myRequest.ContentLength = buf.Length;
            myRequest.ContentType = "application/json";
            myRequest.MaximumAutomaticRedirections = 1;
            myRequest.AllowAutoRedirect = true;
            //發送請求
            Stream stream = myRequest.GetRequestStream();
            stream.Write(buf,0,buf.Length);
            stream.Close();

            //獲取接口返回值
            //通過Web訪問對象獲取響應內容
            HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
            //通過響應內容流創建StreamReader對象，因為StreamReader更高級更快
            StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
            //string returnXml = HttpUtility.UrlDecode(reader.ReadToEnd());//如果有編碼問題就用這個方法
            string returnXml = reader.ReadToEnd();//利用StreamReader就可以從響應內容從頭讀到尾
            reader.Close();
            myResponse.Close();
            return returnXml;

        }
        #endregion

        #region Put請求
        public string Put(string data, string uri)
        {
            //先根據用戶請求的uri構造請求地址
            string serviceUrl = string.Format("{0}/{1}", this.BaseUri, uri);
            //創建Web訪問對象
            HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(serviceUrl);
            //把用戶傳過來的數據轉成“UTF-8”的字節流
            byte[] buf = System.Text.Encoding.GetEncoding("UTF-8").GetBytes(data);

            myRequest.Method = "PUT";
            myRequest.ContentLength = buf.Length;
            myRequest.ContentType = "application/json";
            myRequest.MaximumAutomaticRedirections = 1;
            myRequest.AllowAutoRedirect = true;
            //發送請求
            Stream stream = myRequest.GetRequestStream();
            stream.Write(buf, 0, buf.Length);
            stream.Close();

            //獲取接口返回值
            //通過Web訪問對象獲取響應內容
            HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
            //通過響應內容流創建StreamReader對象，因為StreamReader更高級更快
            StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
            //string returnXml = HttpUtility.UrlDecode(reader.ReadToEnd());//如果有編碼問題就用這個方法
            string returnXml = reader.ReadToEnd();//利用StreamReader就可以從響應內容從頭讀到尾
            reader.Close();
            myResponse.Close();
            return returnXml;

        }
        #endregion


        #region Delete請求
        public string Delete(string data, string uri)
        {
            //先根據用戶請求的uri構造請求地址
            string serviceUrl = string.Format("{0}/{1}", this.BaseUri, uri);
            //創建Web訪問對象
            HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(serviceUrl);
            //把用戶傳過來的數據轉成“UTF-8”的字節流
            byte[] buf = System.Text.Encoding.GetEncoding("UTF-8").GetBytes(data);

            myRequest.Method = "DELETE";
            myRequest.ContentLength = buf.Length;
            myRequest.ContentType = "application/json";
            myRequest.MaximumAutomaticRedirections = 1;
            myRequest.AllowAutoRedirect = true;
            //發送請求
            Stream stream = myRequest.GetRequestStream();
            stream.Write(buf, 0, buf.Length);
            stream.Close();

            //獲取接口返回值
            //通過Web訪問對象獲取響應內容
            HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
            //通過響應內容流創建StreamReader對象，因為StreamReader更高級更快
            StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
            //string returnXml = HttpUtility.UrlDecode(reader.ReadToEnd());//如果有編碼問題就用這個方法
            string returnXml = reader.ReadToEnd();//利用StreamReader就可以從響應內容從頭讀到尾
            reader.Close();
            myResponse.Close();
            return returnXml;

        }
        #endregion
    }
}

 

在Web API發布的同時，.NET提供了兩個程序集：System.Net.Http和System.Net.Http.Formatting。這兩個程序集中最核心的類是HttpClient

以前的用法：創建一個控制台程序，測試HTTP接口的調用。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using WebApplication1;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            RestClient client = new RestClient("http://localhost:2444/");
            string result =  client.Get("api/Values");
            Console.WriteLine(result);
            Console.ReadKey();
        }
    }
}

.NET提供了兩個程序集：System.Net.Http和System.Net.Http.Formatting。這兩個程序集中最核心的類是HttpClient。在.NET4.5中帶有這兩個程序集，而.NET4需要到Nuget里下載Microsoft.Net.Http和Microsoft.AspNet.WebApi.Client這兩個包才能使用這個類，更低的.NET版本就只能表示遺憾了只能用WebRequest/WebResponse或者WebClient來調用這些API了。

//控制台代碼
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Formatting;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using WebApplication1;
using WebApplication1.Models;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            //RestClient client = new RestClient("http://localhost:2444/");
            //string result =  client.Get("api/Values");
            //Console.WriteLine(result);
            //Console.ReadKey();

            var client = new HttpClient();
            //基本的API URL
            client.BaseAddress = new Uri("http://localhost:2444/");
            //默認希望響應使用Json序列化(內容協商機制，我接受json格式的數據)
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            //運行client接收程序
            Run(client);
            Console.ReadLine();
        }
        
        //client接收處理（都是異步的處理）
        static async void Run(HttpClient client)
        {          
            //post 請求插入數據
            var result = await AddPerson(client);
            Console.WriteLine($"添加結果：{result}"); //添加結果：true

            //get 獲取數據
            var person = await GetPerson(client);
            //查詢結果：Id=1 Name=test Age=10 Sex=F
            Console.WriteLine($"查詢結果：{person}");

            //put 更新數據
            result = await PutPerson(client);
            //更新結果：true
            Console.WriteLine($"更新結果：{result}");

            //delete 刪除數據
            result = await DeletePerson(client);
            //刪除結果：true
            Console.WriteLine($"刪除結果：{result}");
        }

        //post
        static async Task<bool> AddPerson(HttpClient client)
        {
            //向Person發送POST請求，Body使用Json進行序列化
            
            return await client.PostAsJsonAsync("api/Person", new Person() { Age = 10, Id = 1, Name = "test", Sex = "F" })
                                //返回請求是否執行成功，即HTTP Code是否為2XX
                                .ContinueWith(x => x.Result.IsSuccessStatusCode);
        }

        //get
        static async Task<Person> GetPerson(HttpClient client)
        {
            //向Person發送GET請求
            return await await client.GetAsync("api/Person/1")
                                     //獲取返回Body，並根據返回的Content-Type自動匹配格式化器反序列化Body內容為對象
                                     .ContinueWith(x => x.Result.Content.ReadAsAsync<Person>(
                    new List<MediaTypeFormatter>() {new JsonMediaTypeFormatter()/*這是Json的格式化器*/
                                                    ,new XmlMediaTypeFormatter()/*這是XML的格式化器*/}));
        }

        //put
        static async Task<bool> PutPerson(HttpClient client)
        {
            //向Person發送PUT請求，Body使用Json進行序列化
            return await client.PutAsJsonAsync("api/Person/1", new Person() { Age = 10, Id = 1, Name = "test1Change", Sex = "F" })
                                .ContinueWith(x => x.Result.IsSuccessStatusCode);  //返回請求是否執行成功，即HTTP Code是否為2XX
        }
        //delete
        static async Task<bool> DeletePerson(HttpClient client)
        {
            return await client.DeleteAsync("api/Person/1") //向Person發送DELETE請求
                               .ContinueWith(x => x.Result.IsSuccessStatusCode); //返回請求是否執行成功，即HTTP Code是否為2XX
        }

    }
}

這個例子就是控制台通過HttpClient這個類調用WebApi中的方法，WebApi就是項目新創建的ValuesController那個控制器，什么都沒動，測試結果如下：