Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
namespace JWTAuthSample
{
    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.Configure<JwtSettings>(Configuration.GetSection("JwtSettings"));
            var jwtSettings= new JwtSettings();
            Configuration.Bind("JwtSettings",jwtSettings);

            services.AddAuthentication(option=>{
                option.DefaultAuthenticateScheme =JwtBearerDefaults.AuthenticationScheme;
                option.DefaultChallengeScheme =JwtBearerDefaults.AuthenticationScheme;
            })
            .AddJwtBearer(option=>{
                option.TokenValidationParameters=new TokenValidationParameters{

                    ValidateIssuer =true,
                    ValidateAudience =true,
                    ValidateLifetime =true,
                    ValidateIssuerSigningKey =true,

                    ValidIssuer = jwtSettings.Issuer,
                    ValidAudience =jwtSettings.Audience,
                    IssuerSigningKey =new SymmetricSecurityKey(System.Text.Encoding.UTF8.GetBytes(jwtSettings.SecretKey))
                };       
            });
            //services.AddAuthorization();
            services.AddControllers();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();

            app.UseRouting();

            
            /*
             *一定要将Authorization引用在Authentication后面 
            */
            app.UseAuthentication();
            app.UseAuthorization();
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}