.NET下通过HttpListener实现简单的Http服务

HttpListener提供一个简单的、可通过编程方式控制的 HTTP 协议侦听器.使用它可以很容易的提供一些Http服务，而无需启动IIS这类大型服务程序。使用HttpListener的方法流程很简单：主要分为以下几步 

1.创建一个HTTP侦听器对象并初始化 

2.添加需要监听的URI 前缀 

3.开始侦听来自客户端的请求 

4.处理客户端的Http请求 

5.关闭HTTP侦听器 

例如：我们要实现一个简单Http服务，进行文件的下载，或者进行一些其他的操作，例如要发送邮件，使用HttpListener监听，处理邮件队列，避免在网站上的同步等待。以及获取一些缓存的数据等等行为 

using System;using System.Collections.Generic;using System.Linq;using System.Net;using System.Text;using System.Threading;using System.Web;using System.IO;using Newtonsoft.Json;namespace HttpListenerApp{ /// <summary> /// HttpRequest逻辑处理 /// </summary> public class HttpProvider {  private static HttpListener httpFiledownload; //文件下载处理请求监听  private static HttpListener httOtherRequest; //其他超做请求监听  /// <summary>  /// 开启HttpListener监听  /// </summary>  public static void Init()  {   httpFiledownload = new HttpListener(); //创建监听实例   httpFiledownload.Prefixes.Add("http://10.0.0.217:20009/FileManageApi/Download/"); //添加监听地址 注意是以/结尾。   httpFiledownload.Start(); //允许该监听地址接受请求的传入。   Thread ThreadhttpFiledownload = new Thread(new ThreadStart(GethttpFiledownload)); //创建开启一个线程监听该地址得请求   ThreadhttpFiledownload.Start();   httOtherRequest = new HttpListener();   httOtherRequest.Prefixes.Add("http://10.0.0.217:20009/BehaviorApi/EmailSend/"); //添加监听地址 注意是以/结尾。   httOtherRequest.Start(); //允许该监听地址接受请求的传入。   Thread ThreadhttOtherRequest = new Thread(new ThreadStart(GethttOtherRequest));   ThreadhttOtherRequest.Start();  }  /// <summary>  /// 执行文件下载处理请求监听行为  /// </summary>  public static void GethttpFiledownload()  {   while (true)   {    HttpListenerContext requestContext = httpFiledownload.GetContext(); //接受到新的请求    try    {     //reecontext 为开启线程传入的 requestContext请求对象     Thread subthread = new Thread(new ParameterizedThreadStart((reecontext) =>       {      Console.WriteLine("执行文件处理请求监听行为");      var request = (HttpListenerContext)reecontext;      var image = HttpUtility.UrlDecode(request.Request.QueryString["imgname"]); //接受GET请求过来的参数；      string filepath = AppDomain.CurrentDomain.BaseDirectory + image;      if (!File.Exists(filepath))      {       filepath = AppDomain.CurrentDomain.BaseDirectory + "default.jpg";  //下载默认图片      }      using (FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read))      {       byte[] buffer = new byte[fs.Length];       fs.Read(buffer, 0, (int)fs.Length); //将文件读到缓存区       request.Response.StatusCode = 200;       request.Response.Headers.Add("Access-Control-Allow-Origin", "*");       request.Response.ContentType = "image/jpg";        request.Response.ContentLength64 = buffer.Length;       var output = request.Response.OutputStream; //获取请求流       output.Write(buffer, 0, buffer.Length);  //将缓存区的字节数写入当前请求流返回       output.Close();      }     }));     subthread.Start(requestContext); //开启处理线程处理下载文件    }    catch (Exception ex)    {     try     {      requestContext.Response.StatusCode = 500;      requestContext.Response.ContentType = "application/text";      requestContext.Response.ContentEncoding = Encoding.UTF8;      byte[] buffer = System.Text.Encoding.UTF8.GetBytes("System Error");      //对客户端输出相应信息.      requestContext.Response.ContentLength64 = buffer.Length;      System.IO.Stream output = requestContext.Response.OutputStream;      output.Write(buffer, 0, buffer.Length);      //关闭输出流，释放相应资源      output.Close();     }     catch { }    }   }  }  /// <summary>  /// 执行其他超做请求监听行为  /// </summary>  public static void GethttOtherRequest()  {   while (true)   {    HttpListenerContext requestContext = httOtherRequest.GetContext(); //接受到新的请求    try    {     //reecontext 为开启线程传入的 requestContext请求对象     Thread subthread = new Thread(new ParameterizedThreadStart((reecontext) =>     {      Console.WriteLine("执行其他超做请求监听行为");      var request = (HttpListenerContext)reecontext;      var msg = HttpUtility.UrlDecode(request.Request.QueryString["behavior"]); //接受GET请求过来的参数；      //在此处执行你需要进行的操作>>比如什么缓存数据读取，队列消息处理，邮件消息队列添加等等。      request.Response.StatusCode = 200;      request.Response.Headers.Add("Access-Control-Allow-Origin", "*");      request.Response.ContentType = "application/json";      requestContext.Response.ContentEncoding = Encoding.UTF8;      byte[] buffer = System.Text.Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(new { success = true, behavior = msg }));      request.Response.ContentLength64 = buffer.Length;      var output = request.Response.OutputStream;      output.Write(buffer, 0, buffer.Length);      output.Close();     }));     subthread.Start(requestContext); //开启处理线程处理下载文件    }    catch (Exception ex)    {     try     {      requestContext.Response.StatusCode = 500;      requestContext.Response.ContentType = "application/text";      requestContext.Response.ContentEncoding = Encoding.UTF8;      byte[] buffer = System.Text.Encoding.UTF8.GetBytes("System Error");      //对客户端输出相应信息.      requestContext.Response.ContentLength64 = buffer.Length;      System.IO.Stream output = requestContext.Response.OutputStream;      output.Write(buffer, 0, buffer.Length);      //关闭输出流，释放相应资源      output.Close();     }     catch { }    }   }  } }}