ASP.NET Core Minimal API之optional route parameter with default value and optional route parameter

 public static void Main(string[] args)
 {
     var builder = WebApplication.CreateBuilder(args);
     var app = builder.Build();

     app.MapGet("/product/{name}", (string name) => $"The product is {name}").WithName("product");
     app.MapGet("/links", (LinkGenerator links) =>
     {
         string link = links.GetPathByName("product", new { name = "big-widget" });
         return $"View the product at {link}";
     });
//下面的string? id必须是string?类型!!，如果是string 类型会出错
     app.MapGet("/test/{name=yjw}/{id?}", (string name, string? id) => string.IsNullOrWhiteSpace(id) ? 
$"the name is {name},don't have id" : $"the name is {name},id is {id}");
     app.Run();
 }