.NetCore配置文件-ConfigurationBuilder读取Json配置（一）

Nuget包安装

//ConfigurationBuilder 依赖：
Microsoft.Extensions.Configuration
//AddJsonFile 依赖：
Microsoft.Extensions.Configuration.Json 
//.Get<Configs>  依赖： 
Microsoft.Extensions.Configuration.Binder

读取方式(本次采用 控制台程序 演示)

在项目中添加JSON配置文件 config.json

{
  "name": "aaa--2",
  "AppSettings": {
    "SystemName": "我的网站---333333333"
  },
  "Domain": {
    "ImgUrl": "aaaa",
    "H5Url": "bbbb"
  },
  "Connections": [
    {
      "Key": "default",
      "Value": "Data Source=.,1433;Initial Catalog=xxx;Persist Security Info=True;User ID=sa;Password=123",
      "DbContext": "DataContext",
      "DBType": "SqlServer"
    }
  ]
}

1、传统的 手动读取配置

        /// <summary>
        /// 传统的 手动读取配置 
        /// 根节点：configRoot["name"]
        /// 二级节点：configRoot.GetSection("Domain:ImgUrl").Value;
        /// 列表节点：configRoot.GetSection("Connections:0:Value"); 
        /// </summary>
        public static void Read1()
        {
            //手动读取配置
            ConfigurationBuilder configBuilder = new ConfigurationBuilder();
            configBuilder.AddJsonFile("config.json",
                optional: false,//optional=false 的时候 如果无文件 会报错
                reloadOnChange: false);//reloadOnChange=如果文件修改了，重新加载配置
            IConfigurationRoot configRoot = configBuilder.Build();

            string name = configRoot["name"];

            string ImgUrl = configRoot.GetSection("Domain:ImgUrl").Value;
            string ImgUrl2 = configRoot["Domain:ImgUrl"];

            var ConnectionsValue = configRoot.GetSection("Connections:0:Value");
        }

2、绑定类读取配置

• Configs.cs

   public class Configs
      {
          public string Name { get; set; }
          public Dictionary<string, string> AppSettings { get; set; }
  
          public List<ConfigConnection> Connections { get; set; }
  
          public ConfigDomain Domain { get; set; }
      }
  
      public class ConfigDomain
      {
          public string ImgUrl { get; set; }
          public string H5Url { get; set; }
      }
  
      public class ConfigConnection
      {
          public string Key { get; set; }
          public string Value { get; set; }
          public string DbContext { get; set; }
          public string DBType { get; set; }
      }

• 读取配置

          /// <summary>
          /// 绑定类读取配置
          /// 绑定一个类，自动完成额配置的读取
          /// NuGet 安装：Microsoft.Extensions.Configuration.Binder
          /// 读取方式：
          /// 1、绑定整个json结构：configRoot.Get<Configs>()
          /// 2、绑定指定节点:configRoot.GetSection("Domain").Get<ConfigDomain>();// Domain 节点的
          /// 3、绑定列表节点:configRoot.GetSection("Connections").Get<List<ConfigConnection>>();//Connections 节点的
          /// </summary>
          public static void Binder()
          {
              ConfigurationBuilder configBuilder = new ConfigurationBuilder();
              configBuilder.AddJsonFile("config.json",
                  optional: false,//optional=false 的时候 如果无文件 会报错
                  reloadOnChange: false);//reloadOnChange=如果文件修改了，重新加载配置
              IConfigurationRoot configRoot = configBuilder.Build();
  
              var config = configRoot.Get<Configs>();//整个json结构
              var domain = configRoot.GetSection("Domain").Get<ConfigDomain>();// Domain 节点的
              var connections = configRoot.GetSection("Connections").Get<List<ConfigConnection>>();//Connections 节点的
  
          }

3、通过DI 注册服务（.net core Web应用 默认采用这种）

• Program.cs

  ServiceCollection services = new ServiceCollection();
  services.AddScoped<HomeController>();
  //注册配置
  ConfigurationBuilder configBuilder = new ConfigurationBuilder();
  configBuilder.AddJsonFile("config.json",
      optional: false,//optional=false 的时候 如果无文件 会报错
      reloadOnChange: true);//reloadOnChange=true 如果文件修改了，重新加载配置
  IConfigurationRoot configRoot = configBuilder.Build(); 
  //services.Configure<Configs>(e => configRoot.Bind(e)); 
  services.AddOptions().Configure<Configs>(e => configRoot.Bind(e));
  using (var sp = services.BuildServiceProvider())
      {
          while (true)
          {
              using (var scope = sp.CreateScope())
              {
                  var c = scope.ServiceProvider.GetRequiredService<HomeController>();
                  c.Index2(); 
                  Thread.Sleep(2000);
              }
          }  
      }

• HomeController.cs

  public class HomeController
      {
          //单例，不支持数据变化(重启更新)，性能高
          private readonly IOptions<Configs> _OptConfig;
          //单例，实时变更（侦听器OnChange） 
          private readonly IOptionsMonitor<Configs> _OptMonitorConfig;
          //作用域注册，单次请求内不变
          private readonly IOptionsSnapshot<Configs> _OptSnapshotConfig;
  
  
          private readonly IServiceProvider _ServiceProvider;
          public HomeController(IOptions<Configs> optConfig, IOptionsMonitor<Configs> optMonitorConfig, IOptionsSnapshot<Configs> optSnapshotConfig, IServiceProvider serviceProvider)
          {
              this._OptConfig = optConfig;
              this._OptMonitorConfig = optMonitorConfig;
              this._OptSnapshotConfig = optSnapshotConfig;
              this._ServiceProvider = serviceProvider;
          }
          public void Index2()
          {
              Console.WriteLine($"[{Thread.CurrentThread.ManagedThreadId}]--_OptConfig_Name={_OptConfig.Value.Name}---{DateTime.Now.ToString("HH:ss")}");
  
              Console.WriteLine($"[{Thread.CurrentThread.ManagedThreadId}]--Snapshot_Name={_OptSnapshotConfig.Value.Name}---{DateTime.Now.ToString("HH:ss")}");
  
              Console.WriteLine($"[{Thread.CurrentThread.ManagedThreadId}]--Monitor_Name={_OptMonitorConfig.CurrentValue.Name}---{DateTime.Now.ToString("HH:ss")}");
  
              Console.WriteLine("\r\n");
               
          }
       }