ASP.NET Core系列：讀取配置文件

本文轉載自查看原文 2019-08-09 11:54 5490 ASP.NET Core

1. 控制台應用

　　新建一個控制台應用，添加兩個Package：

Install-Package Microsoft.Extensions.Configuration
Install-Package Microsoft.Extensions.Configuration.Json

1.1 單個配置文件

　　創建配置文件appsettings.json：

{
  "Data": "10000",
  "ConnectionStrings": {
    "DevContext": "開發庫",
    "ProdContext": "生產庫"
  }
}

　　讀取配置文件：

using System;

using System.IO;
using Microsoft.Extensions.Configuration;

namespace Libing.Core.ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json");
            var config = builder.Build();

            Console.WriteLine(config["Data"]); // 配置鍵
            Console.WriteLine(config.GetSection("ConnectionStrings:DevContext").Value); // 分層鍵
        }
    }
}

　　通過ConfigurationBuilder對象來創建ConfigurationRoot對象，進行讀取配置文件。

　　SetBasePath：設置配置文件基礎路徑

　　AddJsonFile：添加讀取的Json文件

var builder = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("appsettings.json");

　　配置文件可選及修改自動加載設置：

var builder = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("appsettings.json");

　　配置鍵約定：

　　（1）鍵不區分大小寫。例如，ConnectionString 和 connectionstring 被視為等效鍵。

　　（2）分層鍵使用冒號分隔符 (:)

1.2 多個配置文件

　　AddJsonFile：添加多個配置文件。

var builder = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("appsettings.json")
    .AddJsonFile("appsettings.Development.json", optional: true, reloadOnChange: true);

{
  "Data": "10000",
  "ConnectionStrings": {
    "DefaultContext": "默認庫"
  }
}

appsettings.json

{
  "Data": "10000",
  "ConnectionStrings": {
    "DefaultContext": "開發庫"
  }
}

appsettings.Development.json

using System;

using System.IO;
using Microsoft.Extensions.Configuration;

namespace Libing.Core.ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .AddJsonFile("appsettings.Development.json");
            var config = builder.Build();

            Console.WriteLine(config.GetConnectionString("DefaultContext")); // 輸出：開發庫
        }
    }
}

using System;

using System.IO;
using Microsoft.Extensions.Configuration;

namespace Libing.Core.ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.Development.json")
                .AddJsonFile("appsettings.json");
            var config = builder.Build();

            Console.WriteLine(config.GetConnectionString("DefaultContext")); // 輸出：默認庫
        }
    }
}

　　配置鍵相同時，讀取選擇最后一個添加的文件（AddJsonFile）。

　　若要讀取所有添加文件的配置信息，可遍歷ConfigurationRoot的Providers屬性。

using System;

using System.IO;
using Microsoft.Extensions.Configuration;

namespace Libing.Core.ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .AddJsonFile("appsettings.Development.json");
            var config = builder.Build();

            foreach (var provider in config.Providers)
            {
                provider.TryGet("ConnectionStrings:DefaultContext", out string defaultContext);
                Console.WriteLine(defaultContext);
            }

            // 輸出：默認庫
            //      開發庫
        }
    }
}

1.3 配置讀取綁定

　　（1）Key讀取(鍵值對)

{
  "AppID": 10000,
  "Node": {
    "ID": "1",
    "Text": "節點"
  }
}

var builder = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("appsettings.json");
var config = builder.Build();

var appID = config["AppID"];

var builder = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("appsettings.json");
var config = builder.Build();

var nodeid = config.GetSection("Node").GetSection("ID").Value;

　　（2）綁定簡單數據類型 GetValue<T>

　　添加Package：Microsoft.Extensions.Configuration.Binder

using System;

using System.IO;
using Microsoft.Extensions.Configuration;

namespace Libing.Core.ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json");
            var config = builder.Build();

            var appID = config.GetValue<int>("AppID");
            Console.WriteLine(appID);
        }
    }
}

　　（3）綁定到類對象 Get<T>

using System;
using System.Collections.Generic;
using System.Text;

namespace Libing.Core.ConsoleApp
{
    public class Node
    {
        public int ID { get; set; }

        public string Text { get; set; }
    }
}

Node.cs

using System;

using System.IO;
using Microsoft.Extensions.Configuration;

namespace Libing.Core.ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json");
            var config = builder.Build();

            var node = config.GetSection("Node").Get<Node>();

            Console.WriteLine("{0}-{1}", node.ID, node.Text);
        }
    }
}

　　（4）綁定集合對象

{
  "Node": {
    "ID": 1,
    "Text": "節點",
    "Children": [
      {
        "ID": 11,
        "Text": "子節點1"
      },
      {
        "ID": 12,
        "Text": "子節點2"
      },
      {
        "ID": 13,
        "Text": "子節點3"
      }
    ]
  }
}

appsettings.json

using System;

using System.Collections.Generic;

using System.IO;
using Microsoft.Extensions.Configuration;

namespace Libing.Core.ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile(cfg =>
                {
                    cfg.Path = "appsettings.json";
                    cfg.Optional = false;
                    cfg.ReloadOnChange = true;
                });
            var config = builder.Build();

            var children = config.GetSection("Node:Children").Get<IEnumerable<Node>>();
            foreach (var child in children)
            {
                Console.WriteLine("{0}-{1}", child.ID, child.Text);
            }
        }
    }
}

2. API應用程序

　　新建API應用程序，在根目錄下自動創建的Program.cs：

public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseStartup<Startup>();
}

其中，CreateDefaultBuilder創建默認配置，包括：

　　（1）加載IConfiguration配置，讀取文件appsettings.json；

　　（2）加載IConfiguration配置，讀取文件appsettings.[EnvironmentName].json；

　　（3）......

2.1 ConfigureServices中鍵值讀取

　　在根目錄下文件Startup.cs中ConfigureServices()中采用鍵值對方式讀取：

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

    int appid = Configuration.GetValue<int>("AppID");
    var nodes = Configuration.GetSection("Node:Children").Get<IEnumerable<Node>>();
}

2.2 ConfigureServices中使用Options

　　添加安裝包：Microsoft.Extensions.Options.ConfigurationExtensions

{
  "Node": {
    "ID": 1,
    "Text": "NodeText"
  }
}

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

    services.AddOptions();
    services.Configure<Node>(Configuration.GetSection("Node"));
}

　　在控制器中，通過構造函數注入，讀取配置。

public class LogController : ControllerBase
{
    private Node node;
    public LogController(IOptions<Node> option)
    {
        node = option.Value;
    }

    [HttpGet]
    public Node Get()
    {
        int id = node.ID;
        string text = node.Text;

        return node;
    }
}

2.3 讀取自定義配置文件

　　在項目根目錄下，新建配置文件 config.json：

{
  "AppID": "10000"
}

　　修改Program.js，增加讀取config.json文件。

public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
        .ConfigureAppConfiguration((hostingContext, config) =>
        {
            config.SetBasePath(Directory.GetCurrentDirectory());
            config.AddJsonFile("config.json", optional: true, reloadOnChange: true);
        })
        .UseStartup<Startup>();
}

　　在Startup.cs中調用：

public void ConfigureServices(IServiceCollection services)
{
    // 省略其它代碼...
    string appid = Configuration.GetSection("AppID").Value;
}

2.4 獨立類中讀取配置

　　在.Net Framework中，ConfigurationManager類用於讀取配置文件。但在.Net Core中沒有該類，新建類ConfigurationManager用於讀取配置文件。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

using System.IO;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;

namespace Libing.Portal.Core.Api.Common.Configs
{
    public static class ConfigurationManager
    {
        public readonly static IConfiguration Configuration;

        static ConfigurationManager()
        {
            Configuration = new ConfigurationBuilder()
               .SetBasePath(Directory.GetCurrentDirectory())
               .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
               .Build();
        }

        public static T GetSection<T>(string key) where T : class, new()
        {
            return new ServiceCollection()
                .AddOptions()
                .Configure<T>(Configuration.GetSection(key))
                .BuildServiceProvider()
                .GetService<IOptions<T>>()
                .Value;
        }

        public static string GetSection(string key)
        {
            return Configuration.GetValue<string>(key);
        }
    }
}

免責聲明！

本站轉載的文章為個人學習借鑒使用，本站對版權不負任何法律責任。如果侵犯了您的隱私權益，請聯系本站郵箱yoyou2525@163.com刪除。

猜您在找 ASP.NET Core開發-讀取配置文件Configuration ASP.NET Core開發-讀取配置文件Configuration asp.net core 配置文件中文讀取亂碼 asp.net core3.1 讀取配置文件 Asp.Net Core基礎篇之：配置文件讀取 Asp.net Core 和類庫讀取配置文件信息 Asp.Net讀取配置文件 ASP.NET Core 配置文件 ASP.NET Core開發-讀取配置文件Configuration appsettings.json Asp.Net Core 3.1學習-讀取、監聽json配置文件（7）