ASP.NET高效URL重写

public class UrlRouteModule : IHttpModule    {        private static string URL_FLAG = "/q/"; //Url中区别路径和参数的分隔符        private static string URL_SUFFIX = ".aspx"; //对哪种后缀的Url实施Rewrite        public void Init(HttpApplication context)        {            context.BeginRequest += new EventHandler(context_BeginRequest);        }        private void context_BeginRequest(object sender, EventArgs e)        {            HttpApplication app = sender as HttpApplication;            if (app == null) return;            string currentUrl = app.Context.Request.RawUrl;            if (currentUrl.EndsWith(URL_SUFFIX, StringComparison.OrdinalIgnoreCase) == false) //后缀不符合的跳过                return;            int p = currentUrl.IndexOf(URL_FLAG, StringComparison.OrdinalIgnoreCase); //无参的也跳过            if (p == -1) return;            currentUrl = currentUrl.Substring(0, currentUrl.Length - URL_SUFFIX.Length); //去除后缀            string url = string.Format("{0}.aspx", currentUrl.Substring(0, p));            string query = FormmatUrlToQuery(currentUrl.Substring(p + URL_FLAG.Length));            app.Context.RewritePath(url, string.Empty, query);        }        private string FormmatUrlToQuery(string url)        {            int j = 0; //计数器            int len = url.Length;            char[] chars = new char[len];            for (int i = 0; i < len; i++)            {                if (url[i] != '/')                    chars[i] = url[i];                else                {                    if (++j % 2 == 1)                        chars[i] = '=';                    else                        chars[i] = '&';                }            }            return new string(chars);        }        public void Dispose() { }    }