更新：在最近的测试版中，不再可以从ConfigreServices配置安全选项（Identity除外）。您现在需要在调用app. UseJwtBearerAuthentication（）时直接配置JWT选项：

public void Configure(IApplicationBuilder app) {
    app.UseJwtBearerAuthentication(options => {
        // Configure the JWT options here.
    });
}

您忘记在管道中添加OAuth2承载身份验证中间件：

public void Configure(IApplicationBuilder app, IHostingEnvironment env) {
    app.UseStaticFiles();

    app.UseOAuthBearerAuthentication();

    app.UseIdentity();

    app.UseMvc(routes => {
        routes.MapRoute(
            name: "default",
            template: "api/{controller}/{action}/{id?}",
            defaults: new {
                controller = "Home",
                action = "Index"

            });
    });
}

您也没有使用推荐的方法来注册OAuth2承载中间件使用的设置:

public void ConfigureServices(IServiceCollection services) {
    // Not recommended approach.
    services.AddInstance(new OAuthBearerAuthenticationOptions { });

    // Recommended approach.
    services.ConfigureOAuthBearerAuthentication(options => {
        // Configure the options used by the OAuth2 bearer middleware.
    });
}