.net core 读取配置文件

1 使用文件配置提供程序，配置来源可以是json文件、ini文件和xml文件

以json文件作为配置来源读取数据库连接配置实例程序步骤如下：

1）创建一个asp.net coe web api 应用程序 （.net 5 框架）

把配置文件属性 ”复制到输出目录“设置为”如果较新则复制“

2）在项目的 Startup.cs 设置如下代码

        public Startup(IWebHostEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                .AddEnvironmentVariables();

            Configuration = builder.Build();
        }

 3) 读取配置工具类 ConfigurationHelper 如下

    /// <summary>
    /// 读取配置文件工具类
    /// </summary>
    public class ConfigurationHelper
    {
        private static IConfiguration _config;

        public static void Configure(IConfiguration configuration)
        {
            _config = configuration;
        }

        /// <summary>
        /// 获取配置文件中指定键的配置值
        /// </summary>
        /// <param name="key">配置键名</param>
        /// <returns></returns>
        public static string GetKey(string key)
        {
            return _config[key];
        }

        /// <summary>
        /// 获取配置文件中指定键的配置值
        /// </summary>
        /// <param name="key">配置键名</param>
        /// <returns></returns>
        public static string GetSection(string key)
        {
            return _config[key];
        }

        /// <summary>
        /// 使用选项模式对配置进行强类型访问
        /// </summary>
        /// <param name="key">指定配置节</param>
        /// <param name="instance">强类型实例</param>
        public static void BindConfiguration(string key,object instance)
        {
            _config.GetSection(key).Bind(instance);
        }
    }

4) 在 Startup.cs 中的 Configure 添加如下代码初始化配置

            // 配置 ConfigurationHelper
            ConfigurationHelper.Configure(Configuration);

5）配置文件 appsettings.json 如下

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",

  // 单键值对
  "stringKey": "stringKeyValue",

  // 配置组
  "groupKey": {
    "Default": "Server=localhost,1433; Database=MsDemo_Identity; User=sa; Password=yourStrong(!)Password",
    "Conn1": "Server=localhost,1500; Database=MsDemo_Identity; User=sa; Password=yourStrong(!)Password",
    "numberKey": 1,
    "boolKey": true
  },

  // 使用选项模式提供对配置的强类型访问
  "IdentityServerData": {
    "IdentityResources": [
      {
        "Name": "openid",
        "Enabled": true,
        "Required": true,
        "DisplayName": "Your user identifier",
        "UserClaims": [
          "sub"
        ]
      },
      {
        "Name": "profile",
        "Enabled": true,
        "DisplayName": "User profile",
        "Description": "Your user profile information (first name, last name, etc.)",
        "Emphasize": true,
        "UserClaims": [
          "name",
          "family_name",
          "given_name",
          "middle_name",
          "nickname",
          "preferred_username",
          "profile",
          "picture",
          "website",
          "gender",
          "birthdate",
          "zoneinfo",
          "locale",
          "updated_at"
        ]
      }
    ],
    "ApiScopes": [
      {
        "Name": "skoruba_identity_admin_api",
        "DisplayName": "skoruba_identity_admin_api",
        "Required": true,
        "UserClaims": [
          "role",
          "name"
        ]
      }
    ]
  }

}

6）读取配置代码如下

    [ApiController]
    [Route("api/[controller]/[action]")]
    public class ConfigController : ControllerBase
    {
        [HttpGet]
        public IActionResult GetConfig()
        {
            // 读取 单键值对
            string key1Val = ConfigurationHelper.GetKey("stringKey").ToString();

            // 读取 配置组
            string groupKey_default = ConfigurationHelper.GetSection("groupKey:Default");
            string groupKey_Conn1 = ConfigurationHelper.GetSection("groupKey:Conn1");
            long groupKey_numberKey = Convert.ToInt64(ConfigurationHelper.GetSection("groupKey:numberKey"));
            bool groupKey_boolKey = Convert.ToBoolean(ConfigurationHelper.GetSection("groupKey:boolKey"));

            // 使用选项模式对配置进行强类型访问
            IdentityServerData identityServerData = new IdentityServerData();
            ConfigurationHelper.BindConfiguration(nameof(IdentityServerData), identityServerData);

            return new JsonResult("ok");
        }
    }

 

7）与.net framework读取配置对比

以前.net framework读取配置文件（一般为Web.config/app.config）一般是先添加System.Configuration.dll引用，然后使用ConfigurationManager读取配置，如下：

System.Configuration.ConfigurationManager.ConnectionStrings["DBConnect"].ToString().Trim()

 

代码 git 地址： 

https://gitee.com/codechen01/Demo.git 

 

注意：

1  .net 5 可以不添加以下依赖包：

Microsoft.Extensions.Configuration

Microsoft.Extensions.Configuration.Abstractions

Microsoft.Extensions.Configuration.Json 

2  如果 appsettings.json 和 appsettings.Development.json 都配置了同一个键，则取最后添加的配置文件的值为准。