namespace Microsoft.Extensions.Hosting

 {

     //

     // 摘要:

     //     Base class for implementing a long running Microsoft.Extensions.Hosting.IHostedService.

     public abstract class BackgroundService : IHostedService, IDisposable

     {

         protected BackgroundService();

         public virtual void Dispose();

         //

         // 摘要:

         //     Triggered when the application host is ready to start the service.

         //

         // 参数:

         //   cancellationToken:

         //     Indicates that the start process has been aborted.

         public virtual Task StartAsync(CancellationToken cancellationToken);

         //

         // 摘要:

         //     Triggered when the application host is performing a graceful shutdown.

         //

         // 参数:

         //   cancellationToken:

         //     Indicates that the shutdown process should no longer be graceful.

         [AsyncStateMachine(typeof(<StopAsync>d__4))]

         public virtual Task StopAsync(CancellationToken cancellationToken);

         //

         // 摘要:

         //     This method is called when the Microsoft.Extensions.Hosting.IHostedService starts.

         //     The implementation should return a task that represents the lifetime of the long

         //     running operation(s) being performed.

         //

         // 参数:

         //   stoppingToken:

         //     Triggered when Microsoft.Extensions.Hosting.IHostedService.StopAsync(System.Threading.CancellationToken)

         //     is called.

         //

         // 返回结果:

         //     A System.Threading.Tasks.Task that represents the long running operations.

         protected abstract Task ExecuteAsync(CancellationToken stoppingToken);

     }

 }

 internal class TokenRefreshService : BackgroundService

     {

         private readonly ILogger _logger;

         public TokenRefreshService(ILogger<TokenRefresh2Service> logger)

         {

             _logger = logger;

         }

         protected override async Task ExecuteAsync(CancellationToken stoppingToken)

         {

             _logger.LogInformation("Service starting");

             while (!stoppingToken.IsCancellationRequested)

             {

                 _logger.LogInformation(DateTime.Now.ToLongTimeString() + ": Refresh Token!");//在此写需要执行的任务

                 await Task.Delay(, stoppingToken);

             }

             _logger.LogInformation("Service stopping");

         }

     }

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

         public void ConfigureServices(IServiceCollection services)

         {

             services.Configure<CookiePolicyOptions>(options =>

             {

                 // This lambda determines whether user consent for non-essential cookies is needed for a given request.

                 options.CheckConsentNeeded = context => true;

                 options.MinimumSameSitePolicy = SameSiteMode.None;

             });

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

             services.AddSingleton<Microsoft.Extensions.Hosting.IHostedService, TokenRefreshService>();

         }