public static void Main(string[] args) { var builder = new ConfigurationBuilder(); builder.AddJsonFile("appsettings.json"); builder.AddEnvironmentVariables(); var config = builder.Build(); builder.AddEntityFramework(options => options.UseSqlServer(config["Data:DefaultConnection:ConnectionString"])); config = builder.Build(); Console.WriteLine("key1={0}", config["key1"]); Console.WriteLine("key2={0}", config["key2"]); Console.WriteLine("key3={0}", config["key3"]); }