ASP.NET+MVC+Log4net+记录日志笔记

2022-12-01 08:29:33

Log4net 介绍

1、Log4net 是什么？

Log4net 是 Apache 旗下一个开源的日志框架的项目，它是Log4j 的一个复制版。Log4net中定义了多种日志信息输出模式。它可以根据需要将日志输出到控制台、文本文件、windows 日志事件查看器中、括数据库，邮件发送，以便我们可以根据日志快速定位线上系统的问题。

2、Log4net 日志等级

从高到底分别为：OFF > FATAL > ERROR > WARN > INFO > DEBUG > ALL

二、ASP.NET MVC 使用 Log4net 示例

2.1 如何安装 Log4net Log4net

使用Nuget 安装 Log4net（工具-NuGet包管理器-程序包管理器控制台（N））

使用管理NuGet程序包功能找到Log4net进行安装。

2.2 创建 log4net.config 配置文件，并且将该文件的属性“复制到输出目录”修改为 “始终复制。

log4net.config内容如下：

<?xml version="1.0" encoding="utf-8" ?><configuration>  <configSections>    <p name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>  </configSections>    <log4net>    <root>      <level value="ALL" />      <appender-ref ref="LogFileAppender" />      <!--<appender-ref ref="EventLogAppender" />-->    </root>    <!--定义输出到文件-->    <appender name ="LogFileAppender" type="log4net.Appender.RollingFileAppender">      <!--定义文件存放位置-->      <param name="File" value ="Logs\"/>      <param name="AppendToFile" value="true" />      <param name="MaxSizeRollBackups" value="100" />      <param name="MaxFileSize" value="10240" />      <param name="StaticLogFileName" value="false" />      <!--这是按日期产生文件夹-->      <datePattern value="yyyy\\yyyyMM\\yyyyMMdd'.txt'"/>      <param name="RollingStyle" value ="Date" />      <!--不以独占方式记录日志,仅在记录每个日志的最短时间内锁定,因为部署到服务器上遇到了文件被占用无法下载日志-->      <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />      <layout type="log4net.Layout.PatternLayout">        <!--定义输出格式-->        <!--示例 2018-08-20 12:10:49,348 -线程ID:[21] 日志级别:[INFO ] : [日志信息]-->        <!--<conversionPattern value="%newline %n记录时间：%date %n线程ID:[%thread] %n日志级别： %-5level %n错误描述：%message%newline %n"/>-->        <conversionPattern value="%n＝＝＝＝＝＝＝＝＝＝                                  %n【日志级别】%-5level                                  %n【记录时间】%date                                  %n【线程编号】[%thread]                                  %n【执行时间】[%r]毫秒                                  %n【出错文件】%F                                  %n【出错行号】%L                                  %n【出错的类】%logger 属性[%property{NDC}]                                  %n【错误描述】%message                                  %n【错误详情】%newline"/>      </layout>      <!--过滤级别 FATAL > ERROR > WARN > INFO > DEBUG-->      <filter type="log4net.Filter.LevelRangeFilter">        <param name="LevelMin" value="DEBUG" />        <param name="LevelMax" value="FATAL" />      </filter>    </appender>    <!--定义输出到 windows 事件中-->    <appender name="EventLogAppender" type="log4net.Appender.EventLogAppender">      <layout type="log4net.Layout.PatternLayout">        <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline"></conversionPattern>      </layout>    </appender>  </log4net></configuration><?xml version="1.0" encoding="utf-8" ?><configuration>  <configSections>    <p name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>  </configSections>

2.3 新建LogHelper.cs通用日志类

代码如下：

public class LogHelper    {        private ILog _log4Net = null;        private const string DEFAULT_LOGGER_NAME = "Logger";        /// <summary>        /// Prevents a default instance of the <see cref="LogWriter"/> class from being created.        /// </summary>        /// <param name="log4NetInstance">The log4net instance to be used.</param>        private LogHelper(ILog log4NetInstance)        {            _log4Net = log4NetInstance;        }
        /// <summary>        /// Gets a logger with the specified configuration name.        /// </summary>        /// <param name="configName">Name of the logger in the configuration.</param>        /// <returns>The logger obtained.</returns>        /// <exception cref="System.Configuration.ConfigurationException">Thrown when no logger with the specified configuration name was found.</exception>        public static LogHelper GetLogger(string configName)        {            var logger = LogManager.GetLogger(configName);            if (logger == null)            {                throw new ArgumentException(string.Format("No logger configuration named '{0}' was found in the configuration.", configName), "configName");            }            return new LogHelper(logger);        }
        /// <summary>        /// Gets the default.        /// </summary>        public static LogHelper Default        {            get            {                return GetLogger(DEFAULT_LOGGER_NAME);            }        }
        /// <summary>        /// Writes an information level logging message.        /// </summary>        /// <param name="message">The message to be written.</param>        public void WriteInfo(object message)        {            _log4Net.Info(message);        }
        /// <summary>        /// Writes a warning level logging message.        /// </summary>        /// <param name="message">The message to be written.</param>        public void WriteWarning(object message)        {            _log4Net.Warn(message);        }
        /// <summary>        /// Writes a warning level logging message.        /// </summary>        /// <param name="message">The message to be written.</param>        /// <param name="exception">The exception.</param>        public void WriteWarning(object message, System.Exception exception)        {            _log4Net.Warn(message, exception);        }
        /// <summary>        /// Writes the error.        /// </summary>        /// <param name="message">The message to be written.</param>        public void WriteError(object message)        {            _log4Net.Error(message);        }
        /// <summary>        /// Writes the error level logging message..        /// </summary>        /// <param name="message">The message to be written.</param>        /// <param name="exception">The exception.</param>        public void WriteError(object message, System.Exception exception)        {            _log4Net.Error(message, exception);        }
        /// <summary>        /// Writes the fatal error level logging message..        /// </summary>        /// <param name="message">The message to be written.</param>        public void WriteFatal(object message)        {            _log4Net.Fatal(message);        }
        /// <summary>        /// Writes the fatal error level logging message..        /// </summary>        /// <param name="message">The message to be written.</param>        /// <param name="exception">The exception.</param>        public void WriteFatal(object message, System.Exception exception)        {            _log4Net.Fatal(message, exception);        }
        public void DeleteLog()        {            string logDirPath = Path.Combine(Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location), "Log");            if (!Directory.Exists(logDirPath)) return;            int days = 30;            foreach (string filePath in Directory.GetFiles(logDirPath))            {                DateTime dt;                DateTime.TryParse(Path.GetFileNameWithoutExtension(filePath).Replace(@"Log\", "").Replace(".", "-"), out dt);                if (dt.AddDays(days).CompareTo(DateTime.Now) < 0)                {                    File.Delete(filePath);                }            }        }    }

2.4 AssemblyInfo.cs 文件配置log4net.config

特别注意：针对为web项目要加载web项目对应的AssemblyInfo.cs文件中去，这一点很关键要不然就不能输出日志文件



[assembly: log4net.Config.XmlConfigurator(Watch = true, ConfigFileExtension = "config", ConfigFile = @"Configs\log4net.config")]

2.5 自定义日志异常处理文件：MyExceptionFileAttribute.cs

用来处理异常记录日志文件，然后可以指定错误的跳转页面。

public override void OnException(ExceptionContext filterContext) {            base.OnException(filterContext);                   if (!string.IsNullOrWhiteSpace(filterContext.Exception.StackTrace))            {                LogHelper.Default.WriteError(filterContext.Exception.StackTrace);            }                //页面跳转到错误页面                        filterContext.HttpContext.Response.Redirect("/Error");        }

2.6 Global.asax新增Log4Net的配置信息

Application_Start.cs 方法加入下面两行代码：

 // 注册log4net 
 log4net.Config.XmlConfigurator.Configure(); 
 // 注册异常日志文件 
 GlobalFilters.Filters.Add(new MyExceptionFileAttribute());

测试用法

LoginController.cs 代码加一个异常

    public ActionResult Index()        {            int a = 0;            int b = 6 / a;            return View();        }

效果展示：

结语

本文主要简单介绍ASP.NET MVC 使用 Log4net 的过程。具体的一些用法大家也可以互相交流，比如：如何错误日志如何发邮件、数据库的方式存储、日志文件异步存储等等。后续小编会继续更新相关内容和大家一起学习交流。

码农公寓

Log4net 介绍

二、ASP.NET MVC 使用 Log4net 示例

结语

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