ASP.NET MVC：

            RouteTable.Routes.MapRoute(                "ASP.NETMVCRoute",                "ProductInfo/{action}/{id}",                new { controller="Product",action="show",id=RouteParameter.Optional}                );

ASP.NET Web API（WEBHOST）：

            GlobalConfiguration.Configuration.Routes.MapHttpRoute(               "WebAPIRoute",               "api/{controller}/{id}", new { id = RouteParameter.Optional }               );

ASP.NET Web API（SELFHOST）：

HttpSelfHostConfiguration configuration =                 new HttpSelfHostConfiguration("http://loacalhost/selfhost");            using (HttpSelfHostServer selfHostServer = new HttpSelfHostServer(configuration))            {                selfHostServer.Configuration.Routes.MapHttpRoute(                    "DefaultApi", "api/{controller}/{id}", new { id=RouteParameter.Optional});                               selfHostServer.OpenAsync();                Console.Read();            }

ASP.NET Web API 路由系列對象

從上圖的圖表中就可以看出，ASP.NET Web API框架在不同的宿主環境下路由系統中所對應的對象類型是不同的，這里就先給大家介紹在SelfHost環境下的路由系統中的路由對象吧。

SelfHost宿主環境

Web API路由對象(System.Web.Http.Routing)

HttpRoute

    // 摘要:    //     表示自承載（即在 ASP.NET 之外承載）的路由類。    public class HttpRoute : IHttpRoute    {        public HttpRoute(string routeTemplate, HttpRouteValueDictionary defaults, HttpRouteValueDictionary constraints, HttpRouteValueDictionary dataTokens, HttpMessageHandler handler);        public IDictionary<string, object> Constraints { get; }        public IDictionary<string, object> DataTokens { get; }        public IDictionary<string, object> Defaults { get; }        public HttpMessageHandler Handler { get; }        public string RouteTemplate { get; }        public virtual IHttpRouteData GetRouteData(string virtualPathRoot, HttpRequestMessage request);        public virtual IHttpVirtualPathData GetVirtualPath(HttpRequestMessage request, IDictionary<string, object> values);        protected virtual bool ProcessConstraint(HttpRequestMessage request, object constraint, string parameterName, HttpRouteValueDictionary values, HttpRouteDirection routeDirection);    }

可以從上面的定義中看到HttpRoute對象就是代表著在Web API框架中的路由對象了，在HttpRoute類型定義的構造函數中的參數分別表示著路由模板、路由模板對應的默認值、路由匹配條件、注冊的路由附帶的值以及最后的Http請求處理程序，這幾個參數值也分別對應著HttpRoute類型中的幾個屬性，這個自行看一下就明白了。

Web API路由對象集合(System.Web.Http)

HttpRouteCollection

HttpRouteCollectionExtensions

我們先來看一下HttpRouteCollection類型的擴展類型HttpRouteCollectionExtensions吧

    public static class HttpRouteCollectionExtensions    {        public static IHttpRoute MapHttpRoute(this HttpRouteCollection routes, string name, string routeTemplate);        public static IHttpRoute MapHttpRoute(this HttpRouteCollection routes, string name, string routeTemplate, object defaults);        public static IHttpRoute MapHttpRoute(this HttpRouteCollection routes, string name, string routeTemplate, object defaults, object constraints);        public static IHttpRoute MapHttpRoute(this HttpRouteCollection routes, string name, string routeTemplate, object defaults, object constraints, HttpMessageHandler handler);    }

這里大家可以對比上面的路由注冊時的代碼，就可以知道我們在路由集合 添加/注冊 路由的時候是由HttpRouteCollectionExtensions類型的擴展方法來進行操作的，這個時候我們再看一下方法參數最多的那個MapHttpRoute()方法的實現：

public static IHttpRoute MapHttpRoute(this HttpRouteCollection routes, string name, string routeTemplate, object defaults, object constraints, HttpMessageHandler handler)        {            if (routes == null)            {                throw System.Web.Http.Error.ArgumentNull("routes");            }            HttpRouteValueDictionary dictionary = new HttpRouteValueDictionary(defaults);            HttpRouteValueDictionary dictionary2 = new HttpRouteValueDictionary(constraints);            IDictionary<string, object> dataTokens = null;            HttpMessageHandler handler2 = handler;            IHttpRoute route = routes.CreateRoute(routeTemplate, dictionary, dictionary2, dataTokens, handler2);            routes.Add(name, route);            return route;        }

這里大家就可以看到了，HttpRoute對象的創建操作和添加操作是在這擴展方法里執行的，現在我們就可以去看一下HttpRouteCollection類型的定義了，看一下如何創建的IHttpRoute對象：

    public class HttpRouteCollection : ICollection<IHttpRoute>, IEnumerable<IHttpRoute>, IEnumerable, IDisposable    {        public HttpRouteCollection();        public HttpRouteCollection(string virtualPathRoot);        public virtual int Count { get; }        public virtual bool IsReadOnly { get; }        public virtual string VirtualPathRoot { get; }        public virtual void Add(string name, IHttpRoute route);        public IHttpRoute CreateRoute(string routeTemplate, object defaults, object constraints);        public IHttpRoute CreateRoute(string routeTemplate, IDictionary<string, object> defaults, IDictionary<string, object> constraints, IDictionary<string, object> dataTokens);        public virtual IHttpRoute CreateRoute(string routeTemplate, IDictionary<string, object> defaults, IDictionary<string, object> constraints, IDictionary<string, object> dataTokens, HttpMessageHandler handler);        public virtual IHttpR