.Net Standard（.Net Core）实现获取配置信息

一、前言

在.Net Framework框架有专门获取webconfig配置的方法供我们使用，但是在.Net Core或者.Net Standard中没有可以直接使用的方法来获取配置文件信息，下面就来实现获取配置信息。

二、获取配置信息的实现

在.Net Core中，他的配置信息的载体是一个json文件，我们现在就计划所有项目（包含.Net Framework和.Net Standard(.Net Core)框架）都是json文件作为配置的载体。

首先通过Nuget加载如下的包：

Install-Package Microsoft.Extensions.Configuration
Install-Package Microsoft.Extensions.Configuration.Json
Install-Package Microsoft.Extensions.DependencyInjection
Install-Package Microsoft.Extensions.Options
Install-Package Microsoft.Extensions.Options.ConfigurationExtensions

现在我们使用json配置文件的内容有一下格式：

{
  "ConnectionStrings": {
    "CxyOrder": "Server=LAPTOP-AQUL6MDE\\MSSQLSERVERS;Database=CxyOrder;User ID=sa;Password=123456;Trusted_Connection=False;"
  },
  "Appsettings": {
    "SystemName": "PDF .NET CORE",
    "Date": "2017-07-23",
    "Author": "PDF"
  },
  "ServiceUrl": "https://www.baidu.com/getnews"
}

创建PFTConfiguration.cs文件，代码如下：

 public class PFTConfiguration
    {
        /// <summary>
        /// PFTConfiguration.Configuration.GetConnectionString("CxyOrder"); 
        /// PFTConfiguration.Configuration["ServiceUrl"];
        /// PFTConfiguration.Configuration["Appsettings:SystemName"];
        /// </summary>
        public static IConfiguration Configuration { get; set; }
        static PFTConfiguration()
        {
            Configuration = new ConfigurationBuilder()
            .Add(new JsonConfigurationSource { Path = "appsettings.json", ReloadOnChange = true })
            .Build();
        }

        /// <summary>
        /// 获取配置信息
        /// </summary>
        /// <param name="path">json文件类型</param>
        /// <typeparam name="T">返回实体类型</typeparam>
        /// <param name="key">json关键字</param>
        /// <returns></returns>
        public static T GetAppsettings<T>(string key, string path) where T : class, new()
        {
            try
            {
                if (string.IsNullOrWhiteSpace(path))
                {
                    throw new Exception("解析配置错误，配置文件路径为空");
                }
                if (string.IsNullOrWhiteSpace(key))
                {
                    throw new Exception("解析配置错误，配置key为空");
                }
                var config = new ConfigurationBuilder()
                    .SetBasePath(AppDomain.CurrentDomain.BaseDirectory)
                    .Add(new JsonConfigurationSource { Path = path, ReloadOnChange = true })
                    .Build();
                var appconfig = new ServiceCollection()
                    .AddOptions()
                    .Configure<T>(config.GetSection(key))
                    .BuildServiceProvider()
                    .GetService<IOptions<T>>()
                    .Value;
                return appconfig;
            }
            catch (Exception ex)
            {
                throw new Exception("解析配置（对象）异常", ex);
            }

        }


        /// <summary>
        /// 获取配置信息
        /// </summary>
        /// <param name="key">json关键字</param>
        /// <param name="path">json文件类型</param>
        /// <returns></returns>
        public static string GetAppsettings(string key, string path)
        {
            try
            {
                if (string.IsNullOrWhiteSpace(path))
                {
                    throw new Exception("解析配置错误，配置文件路径为空");
                }
                if (string.IsNullOrWhiteSpace(key))
                {
                    throw new Exception("解析配置错误，配置key为空");
                }
                var config = new ConfigurationBuilder()
                    .SetBasePath(AppDomain.CurrentDomain.BaseDirectory)
                    .Add(new JsonConfigurationSource { Path = path, ReloadOnChange = true, Optional = false })
                    .Build();
                var appconfig = config.GetSection(key).Value;
                return appconfig;
            }
            catch (Exception ex)
            {
                throw new Exception("解析配置（字符串）异常", ex);
            }
        }


    }
}