.Net Core 自动读取appsettings.json中数据库连接字符串

    //新建一个类    
    public class AppConfigurtaionServices
    {
        public static IConfiguration Configuration { get; set; }
        static AppConfigurtaionServices()
        {
            //ReloadOnChange = true 当appsettings.json被修改时重新加载            
            Configuration = new ConfigurationBuilder()
            .Add(new JsonConfigurationSource { Path = "appsettings.json", ReloadOnChange = true })
            .Build();
        }
     }

    //需要引用  .net core
    using Microsoft.Extensions.Configuration;
    using Microsoft.Extensions.Configuration.Json;

    //在需要的地方调用  XXX:你对应的名称例如数据库名（master）
    AppConfigurtaionServices.Configuration["ConnectionStrings:XXX"]