怎样获取appsettings.json文件中的值

        /// <summary>
        /// 获取.netcore下的配置文件appsettings.json中的配置项的值
        /// 如："appSettings:DBType"
        /// </summary>
        /// <param name="configItem">配置项</param>
        /// <returns>配置项的值</returns>
        public static string GetNetCoreConfigValue(string configItem)
        {
            //optional:false，配置文件不存在时，报错
            var builder = new ConfigurationBuilder().SetBasePath(Directory.GetCurrentDirectory()).AddJsonFile("appsettings.json",optional:false);
            IConfigurationRoot configuration = builder.Build();
            return configuration.GetValue<string>(configItem) ?? "";
        }

必须先在NuGet中安装

Microsoft.Extensions.Configuration

Microsoft.Extensions.Configuration.Binder

Microsoft.Extensions.Configuration.Json