.net core2.2升级.net core3.1/.net5

    public class Program
    {
        public static void Main(string[] args)
        {
            CreateWebHostBuilder(args).Build().Run();
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup();
    }

using Microsoft.Extensions.Hosting;
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
         Host.CreateDefaultBuilder(args)
             .ConfigureWebHostDefaults(webBuilder =>
             {
                 webBuilder.UseStartup();
             });
    }

//.netCore2.2
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2).AddJsonOptions(
    opt => {
      opt.SerializerSettings.DateFormatString = "yyyy-MM-dd HH:mm";
});
//.net Core3.1
services.AddControllersWithViews(option =>
{
   option.EnableEndpointRouting = false;
}).SetCompatibilityVersion(CompatibilityVersion.Latest).AddControllersAsServices().AddNewtonsoftJson
(
   json =>
   {
      //统一设置JsonResult
      json.SerializerSettings.DateFormatString = "yyyy-MM-dd HH:mm:ss";
   }
);

//.net core2.2 
app.UseMvc(routes =>
{
   routes.MapRoute(
       name: "default_area",
       template: "{area:exists}/{controller=Home}/{action=Index}/{id?}");
   routes.MapRoute(
        name: "default",
        template: "{controller=Home}/{action=Index}/{id?}");
 });

app.UseMvc(routes =>
{
    routes.MapRoute(
    name: "areas",
    template: "{area:exists}/{controller=Home}/{action=Index}/{id?}");
});

//.net 5
app.UseRouting();
app.UseEndpoints(endpoints =>
{
    endpoints.MapControllerRoute(
        name: "default_area",
        pattern: "{area:exists}/{controller=Home}/{action=Index}/{id?}");
    endpoints.MapControllerRoute(
        name: "default",
        pattern: "{controller=Home}/{action=Index}/{id?}");
});

app.UseEndpoints(endpoints =>
{
   endpoints.MapControllerRoute(
      name: "areas",
      pattern: "{area:exists}/{controller=Home}/{action=Index}/{id?}");
});

 services.AddControllersWithViews().AddRazorRuntimeCompilation();