public class Startup

    {

        public Startup(IConfiguration configuration)

        {

            Configuration = configuration;

        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.

        public void ConfigureServices(IServiceCollection services)

        {

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

            services.AddDistributedMemoryCache();

            services.AddSession(option =>

            {

                option.IOTimeout = TimeSpan.FromHours();

                option.IdleTimeout = TimeSpan.FromHours();

                option.Cookie.Name = "aiyu";

            });

        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)

        {

            if (env.IsDevelopment())

            {

                app.UseDeveloperExceptionPage();

            }

            app.UseSession();

            app.UseMvc();

        }

    }

public ActionResult<IEnumerable<string>> Get()

        {

            HttpContext.Session.Set("a", Encoding.UTF8.GetBytes("ss"));

            return new string[] { "value1", HttpContext?.Session.Id};

        }