我想在基于appsettings.json的特定环境ASPNETCORE_ENVironMENT中阅读。

microsoft为core.3.0提供的示例如下：

    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {
            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();
            });
        }
    }

在以前的版本中，我看到的添加特定于环境的appsettings.json的代码是：

    public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
            .SetBasePath(env.ContentRootPath)
            .AddJsonFile("appsettings.json",optional: false,reloadOnChange: true)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json",optional: true)
            .AddEnvironmentVariables();

        Configuration = builder.Build();
    }

我如何更改标准的microsoft示例以包括此内容？