Core 读取配置文件

新建控制台

static void Main(string[] args)
{
Console.WriteLine("Hello World!");

//获取应用程序的当前工作目录 包含当前工作目录路径的字符串，但不包含//以反斜杠（\）结束。
var pathToContentRoot = Directory.GetCurrentDirectory();
//用于构建基于键/值的配置设置，以便在应用程序中使用
var builder = new ConfigurationBuilder()
.SetBasePath(pathToContentRoot)//将基于文件的提供程序的FileProvider设置为PhysicalFileProvider基本路径
.AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)//在构建器的路径中添加JSON配置提供程序
.AddEnvironmentVariables();//添加读取的Microsoft.Extensions.Configuration.IConfigurationProvider来自环境变量的配置值
Coin.Service.Models.CoinAppSettings.CreateInstence(builder.Build());// 获取具有指定键的配置子节   这边开始读取配置文件了！！！

Console.WriteLine("Hello World!");
Console.ReadKey();
}

CreateInstence 这个方法的实现   及 CoinAppSettings这个类库的代码如下

 public class CoinAppSettings
    {
        public DbConnection ConnectionStrings { get; }
        public AppSettings AppSettings { get; }
        public static CoinAppSettings Instance { get; private set; }
        public static void CreateInstence(IConfigurationRoot builder)
        {
            Instance = new CoinAppSettings(builder);
        }
        public CoinAppSettings(IConfigurationRoot builder)
        {
            this.ConnectionStrings = new DbConnection(builder.GetSection("ConnectionStrings"));
            this.AppSettings = new AppSettings(builder.GetSection("AppSettings"));
        }
    }

public class AppSettings
{

public string ApiHost { get; }

public AppSettings(IConfigurationSection section)
{

this.ApiHost = section.GetSection("ApiHost").Value;

}
}