.NET Core Mvc和MySql初接触（三）log4Net全局异常日志

首先到NuGet上安装log4net

安装完成后增加一个log4net配置文件，命名随意，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>

将上面的代码复制到配置文件中，然后到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>();  });//加入全局异常类，日志，放置在ConfigureServices方法内

新建一个类名为HttpGlobalExceptionFilter 的类

public class HttpGlobalExceptionFilter : IExceptionFilter
    {
        private ILog log = LogManager.GetLogger(Startup.repository.Name, typeof(HttpGlobalExceptionFilter));
        public void OnException(ExceptionContext context)
        {
            log.Error(context.Exception);
        }

    }

配置完之后异常，自动写日志就已经实现，接下来写一个静态方法，实现手动写日志

 public class Logger
    {
        public static ILog Write = LogManager.GetLogger(Startup.repository.Name, typeof(HttpGlobalExceptionFilter));//日志记录
    }

在需要写日志的地方就可以这个类的静态方法，例如：Logger.Write.Info(“登录出错:” + e);