1.安装 Nuget 包：Nlog.Web.AspNetCore

1、Nlog;
2、Nlog.Web.AspNetCore

2.添加配置文件： nlog.config  

注意，此处nlog.config最好是小写的，需修改属性使其始终复制

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      autoReload="true"
      internalLogLevel="Info"
      internalLogFile="c:\temp\internal-nlog.txt">

  <!-- enable asp.net core layout renderers -->
  <extensions>
    <add assembly="NLog.Web.AspNetCore"/>
  </extensions>

  <!-- the targets to write to -->
  <targets>
    <!-- write logs to file  -->
    <target xsi:type="File" name="allfile" fileName="c:\temp\nlog-all-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}|
${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}" />

    <!-- another file log, only own logs. Uses some ASP.NET core renderers -->
    <target xsi:type="File" name="ownFile-web" fileName="c:\temp\nlog-own-${shortdate}.log"
            layout="${longdate}|${event-properties:item=EventId_Id}
|${uppercase:${level}}|${logger}|${message}
 ${exception:format=tostring}|url: ${aspnet-request-url}|action: ${aspnet-mvc-action}" />
  </targets>

  <!-- rules to map from logger name to target -->
  <rules>
    <!--All logs, including from Microsoft-->
    <logger name="*" minlevel="Trace" writeTo="allfile" />

    <!--Skip non-critical Microsoft logs and so log only own logs-->
    <logger name="Microsoft.*" maxlevel="Info" final="true" /> <!-- BlackHole without writeTo -->
    <logger name="*" minlevel="Trace" writeTo="ownFile-web" />
  </rules>
</nlog>

3.注册日志依赖

通过修改Program.cs

public class Program
    {
        public static void Main(string[] args)
        {

            //这里添加Nlog
            var logger = NLog.Web.NLogBuilder.ConfigureNLog("nlog.config").GetCurrentClassLogger();
            try
            {
                ////测试Nlog日志输出
                //logger.Debug("init main");
                CreateHostBuilder(args).Build().Run();
            }
            catch (Exception exception)
            {
                logger.Error(exception, "Stopped program because of exception");
                throw;
            }
            finally
            {
                NLog.LogManager.Shutdown();
            }
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                }).UseNLog();//注入日志依赖
    }

4.创建全局日志类ExceptionMiddlewares.cs

 public class ExceptionMiddlewares
    {
        private readonly RequestDelegate next;
        private IHostingEnvironment environment;
        //Nlog构造方法注入
        private readonly ILogger<ExceptionMiddlewares> _logger;
        public ExceptionMiddlewares(RequestDelegate next, IHostingEnvironment environment,
 ILogger<ExceptionMiddlewares> logger)
        {
            _logger = logger;
            this.next = next;
            this.environment = environment;
        }

        public async Task Invoke(HttpContext context)
        {
            try
            {
                await next.Invoke(context);
                var features = context.Features;
            }
            catch (Exception e)
            {
                await HandleException(context, e);
            }
        }

        private async Task HandleException(HttpContext context, Exception e)
        {
            context.Response.StatusCode = 500;
            context.Response.ContentType = "text/json;charset=utf-8;";
            string error = "";

            if (environment.IsDevelopment())
            {
                var json = new { message = e.Message };
             
                _logger.LogError(JsonConvert.SerializeObject(json));
                error = JsonConvert.SerializeObject(json);
            }
            else
                error = "抱歉，出错了";

            await context.Response.WriteAsync(error);
        }
    }

5.在Startup.cs中Configure绑定

//全局异常日志
app.UseMiddleware();