通过代码配置 Log4net

     最近将项目的异常日志模块改造成log4net。在Asp.net MVC3 中的改造非常简单，我们只要继承HandleErrorAttribute类使用自定义类，

使用特性即可统一处理MVC controller 下的 所有的Action 方法的异常。无须try ... catch.... 详情请见我的这篇随笔

http://www.cnblogs.com/ryanding/archive/2010/11/16/1878168.html。我们只要在上文的CustomHandleErrorAttribute方法内植入Log4Net 即可。

具体的留给读者自己去实践了。本文主要讲解如何通过代码配置Log4Net。将程序的异常信息保存到相关文件以及SQLSERVER数据库。

       这里需要提下，将异常存储在文件中的好处就是如果sqlserver出现异常或者网络出现异常。就无法确保将异常正常保存到数据库,

此时异常信息依然会被本地文件记录在案。对于Log4Net 这个开源库我们就不讨论其XML配置。这里着重讲解用代码如何启用Log4Net。

具体配置代码如下：

   public static class Log4netHelper
    {

        //记录异常日志数据库连接字符串
         private const string _ConnectionString = @"data source=your server;initial catalog=your db;integrated security=false;persist security info=True;User ID=sa;Password=1111";

        /// <summary>
        /// 使用SQLSERVER记录异常日志
        /// </summary>
        /// <Author>Ryanding</Author>
        /// <date>2011-05-01</date>
         public static void LoadADONetAppender()
        {
            LoadFileAppender();

            log4net.Repository.Hierarchy.Hierarchy hier =
              log4net.LogManager.GetLoggerRepository() as log4net.Repository.Hierarchy.Hierarchy;

            if (hier != null)
            {
                log4net.Appender.AdoNetAppender adoAppender = new log4net.Appender.AdoNetAppender();
                adoAppender.Name = "AdoNetAppender";
                adoAppender.CommandType = CommandType.Text;
                adoAppender.BufferSize = 1;
                adoAppender.ConnectionType = "System.Data.SqlClient.SqlConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
                adoAppender.ConnectionString = _ConnectionString;
                adoAppender.CommandText = @"INSERT INTO Log ([Date],[Thread],[Level],[Logger],[Message],[Exception]) VALUES (@log_date, @thread, @log_level, @logger, @message, @exception)";
                adoAppender.AddParameter(new AdoNetAppenderParameter { ParameterName = "@log_date", DbType = System.Data.DbType.DateTime, Layout = new log4net.Layout.RawTimeStampLayout() });
                adoAppender.AddParameter(new AdoNetAppenderParameter { ParameterName = "@thread", DbType = System.Data.DbType.String, Size = 255, Layout = new Layout2RawLayoutAdapter(new PatternLayout("%thread")) });
                adoAppender.AddParameter(new AdoNetAppenderParameter { ParameterName = "@log_level", DbType = System.Data.DbType.String, Size = 50, Layout = new Layout2RawLayoutAdapter(new PatternLayout("%level")) });
                adoAppender.AddParameter(new AdoNetAppenderParameter { ParameterName = "@logger", DbType = System.Data.DbType.String, Size = 255, Layout = new Layout2RawLayoutAdapter(new PatternLayout("%logger")) });
                adoAppender.AddParameter(new AdoNetAppenderParameter { ParameterName = "@message", DbType = System.Data.DbType.String, Size = 4000, Layout = new Layout2RawLayoutAdapter(new PatternLayout("%message")) });
                adoAppender.AddParameter(new AdoNetAppenderParameter { ParameterName = "@exception", DbType = System.Data.DbType.String, Size = 4000, Layout = new Layout2RawLayoutAdapter(new ExceptionLayout()) });
                adoAppender.ActivateOptions();
                BasicConfigurator.Configure(adoAppender);
            }


        }

        /// <summary>
        /// 使用文本记录异常日志
        /// </summary>
        /// <Author>Ryanding</Author>
        /// <date>2011-05-01</date>
         public static void LoadFileAppender()
        {
            string currentPath = AppDomain.CurrentDomain.BaseDirectory;
            string txtLogPath = string.Empty;
            string iisBinPath = AppDomain.CurrentDomain.RelativeSearchPath;

            if (!string.IsNullOrEmpty(iisBinPath))
                txtLogPath = Path.Combine(iisBinPath, "ErrorLog.txt");
            else
                txtLogPath = Path.Combine(currentPath, "ErrorLog.txt");

            log4net.Repository.Hierarchy.Hierarchy hier =
             log4net.LogManager.GetLoggerRepository() as log4net.Repository.Hierarchy.Hierarchy;

            FileAppender fileAppender = new FileAppender();
            fileAppender.Name = "LogFileAppender";
            fileAppender.File = txtLogPath;
            fileAppender.AppendToFile = true;

            PatternLayout patternLayout = new PatternLayout();
            patternLayout.ConversionPattern = "记录时间：%date 线程ID:[%thread] 日志级别：%-5level 出错类：%logger property:[%property{NDC}] - 错误描述：%message%newline";
            patternLayout.ActivateOptions();
            fileAppender.Layout = patternLayout;

            //选择UTF8编码，确保中文不乱码。
             fileAppender.Encoding = Encoding.UTF8;

            fileAppender.ActivateOptions();
            BasicConfigurator.Configure(fileAppender);

        }

        /// <summary>
        ///  异常处理
        /// </summary>
        /// <param name="methedType">出现异常方法的类型。例如：MethodBase.GetCurrentMethod().DeclaringType</param>
        /// <param name="errorMsg">错误信息。例如：SaveBuildingPhoto方法出错。Author:开发者名称</param>
        /// <param name="ex"></param>
         public static void InvokeErrorLog(Type methedType, string errorMsg, Exception ex)
        {
            LoadADONetAppender();
            ILog log = log4net.LogManager.GetLogger(methedType);
            log.Info(errorMsg, ex);
        }
    }

在您的数据库执行以下脚本：

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Log]') AND type in (N'U'))
BEGIN
CREATE TABLE [dbo].[Log](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [Date] [datetime] NOT NULL,
    [Thread] [varchar](255) NULL,
    [Level] [varchar](50) NULL,
    [Logger] [varchar](255) NULL,
    [Message] [varchar](4000) NULL,
    [Exception] [varchar](4000) NULL,
PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
END
Go

调用如下：

     public bool Login(string userName, string password)
        {
            try
            {
              //TODO:

            }
            catch(Exception ex)
            {
                Log4netHelper.InvokeErrorLog(MethodBase.GetCurrentMethod().DeclaringType, "登录方法Login出错-Author：ryanding", ex);
                return false;
            }
        }