ASP.Net Core 5.0 MVC AppSettings配置文件读取，Startup 类中ConfigureServices 方法、Configure 方法的使用

{
  "Position": {
    "Title": "EditTool For human",
    "Name": "Joe Smith"
  },//json对象
  "MyKey": "My appsettings.json Value",
  "StudentList": [
    {"sName": "Jack"},
    {"sName":"John"}
  ],//json数组
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }//json对象嵌套
  },
  "AllowedHosts": "*"
}

        public IConfiguration Configuration { get; }
        //构造函数注入 configuration
        public FirstController(IConfiguration configuration)
        {
            Configuration = configuration;
           

        }
        
        public IActionResult Index()
        {
            //配置文件的读取
            ViewBag.Title = Configuration["Position:Title"];//json对象
            ViewBag.MyKey = Configuration["MyKey"];
            ViewBag.sName1 = Configuration["StudentList:0:sName"];//json数组
            ViewBag.sName2 = Configuration["StudentList:1:sName"];
            ViewBag.Default = Configuration["Logging:LogLevel:Default"];//json嵌套对象
            return View();
        }

@*
    For more information on enabling MVC for empty projects, visit https://go.microsoft.com/fwlink/?LinkID=397860
*@
@{
}
<p>  ViewBag.Title 的值:    @ViewBag.Title</p>
<p>  ViewBag.MyKey的值:    @ViewBag.MyKey</p>
<p>  ViewBag.sName1的值:     @ViewBag.sName1</p>
<p>  ViewBag.sName2的值:   @ViewBag.sName2</p>
<p>  ViewBag.Default的值:    @ViewBag.Default</p>

    public void ConfigureServices(IServiceCollection services)
    {

        services.AddDbContext<ApplicationDbContext>(options =>
            options.UseSqlServer(
                Configuration.GetConnectionString("DefaultConnection")));
        services.AddDefaultIdentity<IdentityUser>(
            options => options.SignIn.RequireConfirmedAccount = true)
            .AddEntityFrameworkStores<ApplicationDbContext>();

        services.AddRazorPages();
    }

   public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseHsts();
        }

        app.UseHttpsRedirection();
        app.UseStaticFiles();

        app.UseRouting();

        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapRazorPages();
        });
    }