log4jThe Log4j API tutorial in java provides the interface that applications should code to and provides the adapter components required for implementer’s to create a logging implementation.

The basic Log4j API tutorial in java:

import org.apache.log4j.Logger;

public class LogExample {

public LogExample() {
}
static Logger log = Logger.getLogger(LogExample.class);

public static void main(String argsp[]) {

log.debug(“projectname-modulename-Class-method-Here is some DEBUG”);
log.info(“projectname-modulename-Class-method-Here is some INFO”);
log.warn(“projectname-modulename-Class-method-Here is some WARN”);
log.error(“projectname-modulename-Class-method-Here is some ERROR”);
log.fatal(“projectname-modulename-Class-method-Here is some FATAL”);
log.warn(“projectname-modulename-Class-method-Here is some WARN”);

}
}

 

The sample tutorial to read the log4j configurations from properties file:

import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

public class Example2  {

public static void main(String a[])
{
Logger l=Logger.getLogger(Example2.class);

PropertyConfigurator.configure(“src/prop.properties”);

l.setLevel(Level.DEBUG);
l.debug(“Myprojectname-modulename-Class-method-ok executedddddddddddddd”);
l.info(“projectname-modulename-Class-method-some infoooooooooo”);
l.warn(“projectname-modulename-Class-method-warn msg”);
l.error(“projectname-modulename-Class-method-error msg……”);
l.fatal(“projectname-modulename-Class-method-this is some fatal errrrrrrr”);
}
}

Log4j configurations in properties file: prop.properties

log4j.rootLogger=debug, stdout
log4j.appender.stdout=org.apache.log4j.DailyRollingFileAppender
log4j.appender.stdout.File=logs/dailyrollfile3333.txt
log4j.appender.stdout.DatePattern=’.'yyyy-MM-dd-HH-mm
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%r  [%t]  %p  %c  %m  %d  %n

 

Implementing log4j with Console appender :

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

import org.apache.log4j.ConsoleAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.SimpleLayout;

//ConsoleAppender
public class Example1 {

public static void main(String a[])
{
Logger l=Logger.getLogger(Example1.class);
Layout lay=new SimpleLayout();
ConsoleAppender ap=new ConsoleAppender(lay);

l.addAppender(ap);
l.setLevel(Level.DEBUG);

try{
Class.forName(“oracle.jdbc.driver.OracleDriver”);
l.debug(“driver loaded”);
Connection con=DriverManager.getConnection(“jdbc:oracle:thin:@192.168.1.214:1521:XE”,”kiran”,”kiran”);
l.info(“connection established successfully”);

}catch(ClassNotFoundException e)
{
l.fatal(” OOPS………DriverClass Problem(plz check Driverclass)”);
e.printStackTrace();
}catch(SQLException se)
{
l.fatal(“OOPS…………Db Connection Problem”);
se.printStackTrace();
}
catch(Exception se)
{
l.error(“OOPS…………Db Problem”);
se.printStackTrace();
}

}
}

File Appender tutorial in Log4j :

import java.sql.Connection;
import java.sql.DriverManager;

import org.apache.log4j.*;

//FileAppender

public class Example2  {

public static void main(String a[])
{
Logger l=Logger.getLogger(Example2.class);
try{
Layout lay=new SimpleLayout();
FileAppender ap=new FileAppender(lay,”sample.log”,true);
l.addAppender(ap);
l.setLevel(Level.DEBUG);
}catch(Exception d)
{
l.debug(“log4j stmts problem”);
}
try{
Class.forName(“oracle.jdbc.driver.OracleDriver”);
l.debug(“driver loaded……”);
Connection con=DriverManager.getConnection(“jdbc:oracle:thin:@192.168.1.214:1521:XE”,”kiran”,”kiran”);
l.info(“connection established successfully……….”);

}catch(Exception e)
{
l.fatal(“Db Problem”);
e.printStackTrace();
}
}
}
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