首先到NuGet上安裝log4net 安裝完成後增加一個log4net配置檔案，命名隨意，需要到startup.cs初始化

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<!-- This section contains the log4net configuration settings -->
<log4net>
<appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
<layout type="log4net.Layout.PatternLayout" value="%date [%thread] %-5level %logger - %message%newline" />
</appender>

<!--<appender name="FileAppender" type="log4net.Appender.FileAppender">
  <file value="log-file.log" />
  <appendToFile value="true" />
  <layout type="log4net.Layout.PatternLayout">
    <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
  </layout>
</appender>-->

<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
  <file value="logfile/" />
  <appendToFile value="true" />
  <rollingStyle value="Composite" />
  <staticLogFileName value="false" />
  <datePattern value="yyyyMMdd'.log'" />
  <maxSizeRollBackups value="10" />
  <maximumFileSize value="1MB" />
  <layout type="log4net.Layout.PatternLayout">
    <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
  </layout>
</appender>

<!-- Setup the root category, add the appenders and set the default level -->
<root>
  <level value="ALL" />
  <appender-ref ref="ConsoleAppender" />
  <appender-ref ref="FileAppender" />
  <appender-ref ref="RollingLogFileAppender" />
</root>
</log4net>
</configuration>



 

將上面的程式碼複製到配置檔案中，然後到startup.cs中初始化：

  public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
            repository = LogManager.CreateRepository("NETCoreRepository"); XmlConfigurator.Configure(repository, new FileInfo("log4net.config"));
         
        }
          public static ILoggerRepository repository { get; set; }
            services.AddMvc(options => { options.Filters.Add<Models.HttpGlobalExceptionFilter>();  });//加入全域性異常類，日誌，放置在ConfigureServices方法內
 

配置完之後異常，自動寫日誌就已經實現，接下來寫一個靜態方法，實現手動寫日誌

 public class Logger
    {
        public static ILog Write = LogManager.GetLogger(Startup.repository.Name, typeof(HttpGlobalExceptionFilter));//日誌記錄
    }

在需要寫日誌的地方就可以這個類的靜態方法，例如：Logger.Write.Info(“登入出錯:” + e);