log4j Configuration J2ee,j2se

The first step is to download the log4j jar package and copy it to your system.

Step two, write log4j.properties

Step three, call,

Log4j.properties file content:

#建立mylog, it is the log generator that prints to the console

#org. Apache.log4j.ConsoleAppender indicates the destination is the console

Log4j.appender.mylog = Org.apache.log4j.ConsoleAppender

#target指定输出流

Log4j.appender.mylog.target = System.out

#org. apache.log4j.PatternLayout specify the log output format

log4j.appender.mylog.layout= Org.apache.log4j.PatternLayout

#ConversionPattern给出具体的打印方式

Log4j.appender.mylog.layout.conversionpattern=%-d{yyyy-mm-dd HH:MM:SS} [%c]-[%p]%m%n

#建立my2log the logger to print to the file.

#RollingFileAppender scrolling Print information to a file, the file is limited

#FileAppender file size is not limited

Log4j.appender.my2log = Org.apache.log4j.RollingFileAppender

#File Specify the way to print to that file.

Log4j.appender.my2log.File = D://logger//mylog.log

#MaxFileSize the size of the specified file

Log4j.appender.my2log.MaxFileSize = 50KB

#MaxBackupIndex The maximum number of backup files for a specified file

Log4j.appender.my2log.MaxBackupIndex = 1

#org. apache.log4j.PatternLayout specify the log output format

log4j.appender.my2log.layout= Org.apache.log4j.PatternLayout

#ConversionPattern给出具体的打印方式

Log4j.appender.my2log.layout.conversionpattern=%-d{yyyy-mm-dd HH:MM:SS} [%c]-[%p]%m%n

#rootLogger specifies that the logger used has mylog and My2log

#warn Specify the type of print information: info: Debug Info warn: Warning message error: Wrong message

#级别从底到高: Info-->warn-->error

#定义info can print all the information;

#定义warn can print warn and error, unable to print info

#定义error can print error, can't print info and warn

Log4j.rootlogger = Info,mylog,my2log

Called in J2SE:

public class Test {

public static void Main (string[] args) {

Logger log = Logger.getlogger (Test.class.getName ());

Propertyconfigurator.configure ("D://testlog4j//lg4j.properties (Physical Address of File)");

for (int i=0;i<100;i++) {

Log.warn ("斕 cavity");

Log.error ("fff");

Log.info ("123");

}

}

}

The web system requires a servlet to start log4j

The servlet is as follows:

Import java.io.IOException;

Import Javax.servlet.ServletContext;

Import javax.servlet.ServletException;

Import Javax.servlet.http.HttpServlet;

Import Javax.servlet.http.HttpServletRequest;

Import Javax.servlet.http.HttpServletResponse;

Import Org.apache.commons.logging.impl.Log4JCategoryLog;

Import Org.apache.log4j.Logger;

Import Org.apache.log4j.PropertyConfigurator;

Import com.sun.org.apache.bcel.internal.verifier.exc.StaticCodeConstraintException;

public class Logprint extends HttpServlet {

@Override

protected void doget (HttpServletRequest arg0, HttpServletResponse arg1) throws Servletexception, IOException {

}

@Override

protected void DoPost (HttpServletRequest arg0, HttpServletResponse arg1) throws Servletexception, IOException {

}

@Override

public void Init () throws Servletexception {

ServletContext SCT = Getservletcontext ();

String prefix = Sct.getrealpath ("/");

String file = Getinitparameter ("log4j");

if (file!= null) {

Propertyconfigurator.configure (Prefix+file);

}

System.out.println ("LOG4J sucess!!!!!");

}

The Web.xml configuration is as follows: <servlet> <servlet-name>log</servlet-name> <servlet-class>cn.**.*.log4j. lo4jtest</servlet-class> <init-param> <param-name>log4j</param-name> <param-value> Web-inf/lg4j.properties (relative path in the system) </param-value> </init-param> <load-on-startup>1</ Load-on-startup> </servlet> Next is called in the class: public class Operate {private Logger Logger = Logger.getlogger ("Operat E ");     Public DatabaseConnection Getdbconn () {Logger.info ("OPERAT1: Created"); return dbconn; }