教程吧

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; 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 { } } } } } }

调用方式：注意这里启动程序必须以管理员身份运行，因为上午的监听需要开启端口，所有需要以管理员身份运行。 

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace HttpListenerApp { class Program { static void Main(string[] args) { //开启请求监听 HttpProvider.Init(); } } }

执行后的结果为：

这里通过一个简单的控制程序在里面使用HttpListener实现了简单的Http服务程序。里面有少量的线程和和异步处理，比如收到行为信息请求可以先返回给用户，让用户不用同步等待，就可以执行下一步操作，又比如实现的简单邮件服务器，将请求发给HttpListener接收到请求后就立即返回，交给队列去发送邮件。邮件的发送会出现延迟等待等情况出现，这样就不用等待。

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