{"Logging": {"LogLevel": {"Default": "Information","Microsoft": "Warning","Microsoft.Hosting.Lifetime": "Information"}},"AllowedHosts": "*","Tecent": {"Qzone": {"Url": "http://i.qq.com","CName": "QQ空间","Age": 15},"Weixin": {}}
}

    public interface ITecentConfig{QzoneConfig Qzone { get; set; }}

    public class TecentConfig : ITecentConfig{public QzoneConfig Qzone { get; set; }}

    public class QzoneConfig{public string Url { get; set; }public string CName { get; set; }public int Age { get; set; }}

    public static class ServiceCollectionExtensions{public static void ConfigureApplicationServices(this IServiceCollection services, IConfiguration configuration){ITecentConfig tencentConfig = services.ConfigureStartupConfig<ITecentConfig, TecentConfig>(configuration.GetSection("Tecent"));//由于已经通过依赖注入了，并且单例模式，下面通过依赖注入读取配置。
            }public static TConfig ConfigureStartupConfig<TConfig>(this IServiceCollection services, IConfiguration configuration) where TConfig : class, new(){if (services == null)throw new ArgumentNullException(nameof(services));if (configuration == null)throw new ArgumentNullException(nameof(configuration));var config = new TConfig();configuration.Bind(config);services.AddSingleton(config);//.NET Core DI 为我们提供的实例生命周其包括三种：//Transient： 每一次GetService都会创建一个新的实例//Scoped：  在同一个Scope内只初始化一个实例 ，可以//          理解为（ 每一个request级别只创建一个实例，同一个http request会在一个 scope内）//Singleton ：整个应用程序生命周期以内只创建一个实例return config;}public static IConfig ConfigureStartupConfig<IConfig, ConfigImpl>(this IServiceCollection services, IConfiguration configuration)where ConfigImpl : class, IConfig, new(){if (services == null)throw new ArgumentNullException(nameof(services));if (configuration == null)throw new ArgumentNullException(nameof(configuration));var config = new ConfigImpl();configuration.Bind(config);services.AddSingleton(typeof(IConfig), config);return config;}}

    public class Startup{public Startup(IConfiguration configuration){Configuration = configuration;}public IConfiguration Configuration { get; }public void ConfigureServices(IServiceCollection services){services.Configure<CookiePolicyOptions>(options =>{options.CheckConsentNeeded = context => true;});services.ConfigureApplicationServices(Configuration);//注册我们自定义的服务//注册自定义的模型绑定
            services.AddMvc().AddNewtonsoftJson();services.AddRazorPages();}
}

    public class HomeController : Controller{private ITecentConfig _tecentConfig;public HomeController(ITecentConfig tecentConfig){_tecentConfig = tecentConfig;}public IActionResult About(){return Content(string.Format("这个是 About 介绍。{0}: {1}。HashCode：{2}", _tecentConfig.Qzone.CName, _tecentConfig.Qzone.Url,_tecentConfig.GetHashCode()));}}