C# log4net 日志输出的实现示例

思路：
1.安装插件：安装log4net
2.使用配置：添加log4net.config配置文件
3.输出日志文件格式：添加日志配置
4.AssemblyInfo.cs中配置

第一步：安装log4net

第二步：添加log4net.config配置文件

新增log4net.config配置文件,内容如下，与Program.cs同一目录即可。

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net"/>
</configSections>
<log4net>
<!--level取值：OFF FATAL ERROR WARN INFO DEBUG ALL -->
<logger name="loginfo">
<level value="ALL"/>
<appender-ref ref="InfoAppender"/>
</logger>
<appender name="InfoAppender" type="log4net.Appender.RollingFileAppender">
<param name="File" value="log\\"/>
<lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
<param name="AppendToFile" value="true"/>
<param name="MaxFileSize" value="10240"/>
<param name="StaticLogFileName" value="false"/>
<param name="DatePattern" value="yyyy-MM-dd&quot;.txt&quot;"/>
<param name="RollingStyle" value="Date"/>
<layout type="log4net.Layout.PatternLayout">
<param name="ConversionPattern" value="％d [％p] - ％m％n"/>
</layout>
</appender>
</log4net>
</configuration>

并设置 – 属性 – 复制到输出目录为：始终复制

第三步：添加日志配置

在文件Program.cs应用程序主入口加入：

LogUtils.SetConfig(new FileInfo(Application.StartupPath + @"\log4net.config"));

LogUtils.cs 写入日志公共类

class LogUtils
{
private static readonly ILog loginfo = LogManager.GetLogger("loginfo");

/// <summary>
/// 从缺省配置文件获取日志配置
/// </summary>
public static void SetConfig()
{
XmlConfigurator.Configure();
}

/// <summary>
/// 从指定配置文件获取日志配置
/// </summary>
/// <param name="configFile">指定的配置文件</param>
public static void SetConfig(FileInfo configFile)
{
XmlConfigurator.Configure(configFile);
}

/// <summary>
/// 生成分类日志
/// </summary>
/// <param name="info">日志信息</param>
/// <param name="dirName">保存目录名,形如d:\log\aaa</param>
private static void WriteSortLog(string info, string dirName)
{
try
{
if (false == System.IO.Directory.Exists(dirName))
{
System.IO.Directory.CreateDirectory(dirName);
}
string path = dirName + "\\" + DateTime.Now.ToString("yyyyMMdd") + ".txt";
StreamWriter sw = new StreamWriter(path, true, System.Text.Encoding.Default);
sw.WriteLine(DateTime.Now.ToString("HH:mm:ss: ") + info);
sw.Close();
}
catch (Exception ex)
{
string expMsg = "WriteSortLog异常：" + ex.Message + Environment.NewLine + ex.StackTrace;

if (ex.InnerException != null)
expMsg += Environment.NewLine + "InnerException:" + ex.InnerException.Message;

Error(expMsg, ex);
}
}

/// <summary>
/// Info级 常规日志
/// </summary>
/// <param name="info">日志信息</param>
public static void Info(string info)
{
if (loginfo.IsInfoEnabled)
{
loginfo.Info(info);
}
}

/// <summary>
/// Info 先生成常规日志，然后在指定目录另外创建一份日志
/// 主要用来需要对日志进行分类时使用
/// </summary>
/// <param name="info"></param>
/// <param name="dirName"></param>
public static void Info(string info, string dirName)
{
if (loginfo.IsInfoEnabled)
{
//生成常规日志
loginfo.Info(info);

//生成分类日志
WriteSortLog(info, dirName);
}
}

/// <summary>
/// Debug级 常规日志
/// </summary>
/// <param name="info">日志信息</param>
public static void Debug(string info)
{
if (loginfo.IsDebugEnabled)
{
loginfo.Debug(info);
}
}

/// <summary>
/// Debug级 异常日志
/// </summary>
/// <param name="info">日志信息</param>
/// <param name="exp">异常信息</param>
public static void Debug(string info, Exception exp)
{
if (loginfo.IsDebugEnabled)
{
loginfo.Debug(info, exp);
}
}

/// <summary>
/// Error级 常规的日志
/// </summary>
/// <param name="info">日志信息</param>
public static void Error(string info)
{
if (loginfo.IsErrorEnabled)
{
loginfo.Error(info);
}
}

/// <summary>
/// Error 异常日志
/// </summary>
/// <param name="info">日志信息</param>
/// <param name="exp">异常信息</param>
public static void Error(string info, Exception exp)
{
if (loginfo.IsErrorEnabled)
{
loginfo.Error(info, exp);
}
}

/// <summary>
/// Fatal级 常规日志
/// </summary>
/// <param name="info">日志信息</param>
public static void Fatal(string info)
{
if (loginfo.IsFatalEnabled)
{
loginfo.Fatal(info);
}
}

/// <summary>
/// Fatal级 异常日志
/// </summary>
/// <param name="info">日志信息</param>
/// <param name="exp">异常信息</param>
public static void Fatal(string info, Exception exp)
{
if (loginfo.IsFatalEnabled)
{
loginfo.Fatal(info, exp);
}
}

/// <summary>
/// Warn级 常规日志
/// </summary>
/// <param name="info">日志信息</param>
public static void Warn(string info)
{
if (loginfo.IsWarnEnabled)
{
loginfo.Warn(info);
}
}

/// <summary>
/// Warn级 异常日志
/// </summary>
/// <param name="info">日志</param>
/// <param name="exp">异常信息</param>
public static void Warn(string info, Exception exp)
{
if (loginfo.IsWarnEnabled)
{
loginfo.Warn(info, exp);
}
}
}

第四步：AssemblyInfo.cs中配置 Watch = true

在项目Properties文件夹下AssemblyInfo.cs中加入：

[assembly: log4net.Config.XmlConfigurator(Watch = true)]

最后通过

LogUtils.Error(“错误日志”);
LogUtils.Info(“正常输出日志”);
LogUtils.Warn(“温馨提示日志”);

最后启动项目：会在项目debug目录下输出日志文件夹log内

来源：https://blog.csdn.net/qq_16771097/article/details/120845149