.NET 5应用如何在数据层（非控制器）读取appsettings.json的配置值

步骤1：在Startup类中引入IConfiguration实例 #

ASP.NET Core默认已将加载完appsettings.json的IConfiguration实现注册到服务容器，直接在Startup构造函数中接收即可，无需自行实现IConfiguration接口：

public class Startup
{
    // 新增私有字段存储配置实例
    private readonly IConfiguration _configuration;

    public Startup(IConfiguration configuration)
    {
        _configuration = configuration;
    }

    // 原有ConfigureServices、Configure方法保留即可
}

步骤2：修正Scheduler实例化逻辑 #

实例化Scheduler时直接传入已经加载好配置的_configuration字段即可：

public void ConfigureServices(IServiceCollection services)
{            
    services.AddControllers();

    services.AddSingleton(typeof(Config));
    services.AddSingleton(typeof(TokenHelper));
           
    // 传入配置实例即可完成实例化
    Scheduler obj = new Scheduler(_configuration);
    services.AddSingleton<Scheduler>(obj);

    Thread t1 = new Thread(new ThreadStart(obj.CallScheduler));
    t1.Start();
}

可选优化：强类型绑定配置（更推荐） #

为了避免硬编码配置Key、实现类型安全，建议把配置绑定到实体类使用：

1. 定义配置对应实体类

public class AppSettings
{
    public int DelayTimer { get; set; }
    public string Server { get; set; }
    public string DefaultDatabase { get; set; }
}

2. 在ConfigureServices中添加绑定

services.Configure<AppSettings>(_configuration);

3. 修改Scheduler构造函数注入强类型配置

public class Scheduler
{    
    private readonly int _delayTime;

    public Scheduler(IOptions<AppSettings> settings)
    {           
        _delayTime = settings.Value.DelayTimer;
        CallScheduler();
    }
}

内容的提问来源于stack exchange，提问作者abhishek