通俗的讲，Web服务器传送(serves)页面使浏览器可以浏览，然而应用程序服务器提供的是客户端应用程序可以调用(call)的方法(methods)。确切一点，你可以说：Web服务器专门处理HTTP请求(request)，但是应用程序服务器是通过很多协议来为应用程序提供(serves)商业逻辑(business logic)。

常用的web Server

namespace HttpListenerDemo
{static class Program{/// <summary>/// 应用程序的主入口点。/// </summary>
        [STAThread]static void Main(){HttpListener httpListenner;httpListenner = new HttpListener();httpListenner.AuthenticationSchemes = AuthenticationSchemes.Anonymous;httpListenner.Prefixes.Add("http://localhost:8090/");httpListenner.Start();new Thread(new ThreadStart(delegate {try{loop(httpListenner);}catch (Exception){httpListenner.Stop();}})).Start();}private static void loop(HttpListener httpListenner){while (true) {HttpListenerContext context = httpListenner.GetContext();HttpListenerRequest request = context.Request;HttpListenerResponse response = context.Response;Servlet servlet = new MyServlet();servlet.onCreate();if (request.HttpMethod == "POST") {servlet.onPost(request, response);}else if (request.HttpMethod == "GET"){servlet.onGet(request, response);}response.Close();}}}
}public class Servlet{public virtual void onGet(System.Net.HttpListenerRequest request, System.Net.HttpListenerResponse response) { }public virtual void onPost(System.Net.HttpListenerRequest request, System.Net.HttpListenerResponse response) { }public virtual void onCreate(){}}public class MyServlet : HttpListenerDemo.Servlet{public override void onCreate(){base.onCreate();}public override void onGet(HttpListenerRequest request, HttpListenerResponse response){Console.WriteLine("GET:" + request.Url);byte[] buffer = Encoding.UTF8.GetBytes("OK");System.IO.Stream output = response.OutputStream;output.Write(buffer, 0, buffer.Length);// You must close the output stream.
            output.Close();//listener.Stop();
        }public override void onPost(HttpListenerRequest request, HttpListenerResponse response){Console.WriteLine("POST:" + request.Url);byte[] res = Encoding.UTF8.GetBytes("OK");response.OutputStream.Write(res, 0, res.Length);}}