netcore 控制台应用程序 appsettings.json

using System;
using System.Runtime;
using ClassLibrary1;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new HostBuilder().ConfigureAppConfiguration((hostContext, configApp) =>
            {
                configApp.AddJsonFile("appsettings.json");
            })
            .ConfigureServices((hostContext, services) =>
            {
                //注入依赖
                services.AddTransient<IClass1, Class1>();
            }).UseConsoleLifetime();

            var host = builder.Build();
            using (var serviceScope = host.Services.CreateScope())
            {
                var services = serviceScope.ServiceProvider;
                var myConfig = services.GetRequiredService<IConfiguration>();
                //获取注入类
                var myService = services.GetRequiredService<IClass1>();

                //获取配置连接字符串
                string defaultConnectionString = myConfig.GetConnectionString("DefaultConnectionString");

                //调用接口方法名称
                Console.WriteLine(myService.test());
                Console.ReadKey();
            }
        }
    }
}