public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
            .ConfigureLogging(loggingBuilder =>
            {    //设置log4net配置文件
                loggingBuilder.AddLog4Net("ConfigFile/log4net.Config");
            })
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });