C#log4net use of the logging component

I. Introduction of Log4net

Log4net is a well-known open source component for. NET development. It uses a set of XML-configured log engines that divide logs into different levels: FATAL, ERROR, WARN, INFO, DEBUG, all (allow all log requests) and off (deny all log requests), default to DEBUG, The first five can be seen as a bit like what we normally do in debugging an application, and in the compiler it leaves hints such as errors, warnings, and their error levels falling.

We continue to look at the core components of log4net, log4net mainly consists of five parts, namely Logger,appenders, Filters, Layouts and object renders.

Log4net is used to record the log, the program can be run in the process of information output to some places (files, databases, eventlog, etc.), the log is the program's black box, can be
The log looks at the system's running process to discover problems with the system. The role of the log: the process of running the steps, the success of the failure to record, the critical data recorded down the system problems. Log4j.
For the Web site, you can not display the exception information to the user, the exception information can only be recorded to the log, the issue of the log file sent to developers, you can know the problem.

Configuring the Log4net Environment

(1) Create a new WebApplication

(2) Add a reference to the Log4net.dll (Bin\net\2.0\release cannot reference the debug version) (copy the corresponding DLL file to the Lib folder in the project.) )

(3) Add configuration in Web. config (or app. config), see Remarks

(4) Initialization: Add log4net at the beginning of the program. Config.XmlConfigurator.Configure (); Do not add to the page load

(5) Logmanager.getlogger (typeof) where the log is to be printed. Debug ("Information");. Pass the log class name that you want to log by Logmanager.getlogger get the ilog of this class (so that in the log file you can see which class output the log is), and then call the Debug method output message. Because there is more than one place inside a class to print the log, Ilog is generally declared as a static field.
Private static ILog Logger=logmanager.getlogger (typeof (Test))
Output error message with the Ilog.error method, the second parameter can pass the exception object. Log. Error ("* * * * +ex"), log. Error ("* * * ERROR", ex)
Test code:

Appender: The logs can be exported to different locations, with different output targets corresponding to different appender:rollingfileappender (scrolling files), Adonetappender (database), Smtpappender (mail), etc.

Level: Identifies the important level of this log information. None>fatal>error>warn>debug>info>all, set a level, then the log below this level will not be written into the Appender.

Log4net can also set a number of appender, can be realized at the same time log to file, data, send mail, etc. can be set different levels of appender, can achieve the normal level are recorded to the file, error above level send mail , can be implemented for different classes to set different Appender, you can also customize the Appender, so that you can implement the error message to send text messages and so on.

(*) In addition to log4net, there are Enterprise Library logging application Block, Apache Commonlog and Nlog, etc., are similar.

Log4net Configuration
<configuration>
<configSections>
<section name= "log4net" type= "log4net. Config.log4netconfigurationsectionhandler, log4net "/>
</configSections>
<log4net>
<!--Define some output appenders--
<appender name= "Rollinglogfileappender" type= "log4net. Appender.rollingfileappender ">
<file value= "Test.txt"/>
<appendtofile value= "true"/>
<maxsizerollbackups value= "Ten"/>
<maximumfilesize value= "1024KB"/>
<rollingstyle value= "Size"/>
<staticlogfilename value= "true"/>
<layout type= "log4net. Layout.patternlayout ">
<conversionpattern value= "%date [%thread]%-5level%logger-%message%newline"/>
</layout>
</appender>
<root>
<level value= "DEBUG"/>
<appender-ref ref= "Rollinglogfileappender"/>
</root>
</log4net>
</configuration>