.NET Core 读取appsettings.json配置文件

1、appsettings.json配置文件

{
  "Logging": {
    "IncludeScopes": false,
    "Debug": {
      "LogLevel": {
        "Default": "Warning"
      }
    },
    "Console": {
      "LogLevel": {
        "Default": "Warning"
      }
    },
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "JwtSettings": {
    "Issuer": "http://localhost:5200",
    "Audience": "http://localhost:5200",
    "SecretKey": "ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789"
  },
  "AllowedHosts": "*"
}

2、Startup.cs文件

public void ConfigureServices(IServiceCollection services)
{
    string audience = string.Empty;
    string issuer = string.Empty;
    string secretKey = string.Empty;

    #region 从appsettings.json文件中读取JwtSettings相关配置信息

    services.Configure<JwtSettings>(Configuration.GetSection("JwtSettings"));
    JwtSettings setting = new JwtSettings();
    Configuration.Bind("JwtSettings", setting);

    audience = setting.Audience;
    issuer = setting.Issuer;
    secretKey = setting.SecretKey;

    #endregion

    services.Configure<JwtSettings>(Configuration.GetSection("JwtSettings"));

    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}

3、JwtSettings.cs文件

public class JwtSettings
{
    /// <summary>
    /// 证书颁发者
    /// </summary>
    public string Issuer { get; set; }

    /// <summary>
    /// 允许使用的角色
    /// </summary>
    public string Audience { get; set; }

    /// <summary>
    /// 加密字符串
    /// </summary>
    public string SecretKey { get; set; }
}

4、Controller 

using Microsoft.Extensions.Options;
using Microsoft.Extensions.Configuration;

public class HomeController : Controller
{
    private IOptions<JwtSettings> _setting;
    private IConfiguration _configuration;

    public HomeController(IOptions<JwtSettings> setting)
    {
        _setting = setting;
        _configuration = configuration;
    }

    public IActionResult Index()
    {
        JwtSettings setting = new JwtSettings();
        _configuration.Bind("JwtSettings", setting);

        string secretKey = _setting.Value.SecretKey;
        string issuer = _setting.Value.Issuer;
        string audience = _setting.Value.Audience;

        return View();
    }
}