using
 
 Microsoft.AspNetCore.Hosting;

namespace MyWeb
{
    class Program
    {
        static void Main(string[] args)
        {
            var host = new WebHostBuilder()
                .UseKestrel()           // 指定WebServer為Kestrel
                .UseStartup<Startup>()  // 配置WebHost
                .Build();

            host.Run();                 
 
// 啟動WebHost
        }
    }
}

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.Logging;
using Microsoft.AspNetCore.Http;

namespace MyWeb
{
    class Startup
    {
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            app.Run(c 
 
=> {
                return c.Response.WriteAsync("Hello dotnet core.");
            });
        }
    }
}

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.Logging;
using Microsoft.AspNetCore.Http;

namespace MyWeb
{
    class Startup
    {
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            app.Run(c => {
                var req = c.Request.Path.ToString().TrimStart(‘/‘);
                var res = string.Empty;

                switch (req)
                {
                    case "1":
                        res = "one";
                        break;
                    case "2":
                        res = "two";
                        break;
                    default:
                        res = "none";
                        break;                        
                }

                var mtd = string.Empty;
                switch (c.Request.Method)
                {
                    case "GET":
                        mtd = "請求方式: get";
                        break;
                    case "POST":
                        mtd = "請求方式：post";
                        break;
                    default:
                        mtd = "請求方式：none";
                        break;
                }

                return c.Response.WriteAsync(res);
            });
        }
    }
}

我們並沒有看到我們使用Nuget應用的兩個包，這也說明.NetCore2.0做了運行時包倉優化。參考：02、NetCore2.0--引用系統和第三方包時的優化

03、手工創建Asp.Net Core 2.0 web應用程序（探索最小架構）