Create Custom Pattern using log4j2 in java.

Log4j2 custom pattern example in java .

1. Create custom pattern, first we need to create plugin. For example I need to print TransactionLogId in logs.

TransactionLogIdConverter.java

@Plugin(name="TransactionIdConverter", category = "Converter")

@ConverterKeys({"trnLogid","trscId"})

public class TransactionLogIdConverter extends LogEventPatternConverter{

    protected TransactionLogIdConverter(String name, String style) {

        super(name, style);

    }

    public static TransactionLogIdConverter newInstance(String[] options) {

        return new TransactionLogIdConverter("trnLogid",Thread.currentThread().getName());

    }

    @Override

    public void format(LogEvent event, StringBuilder toAppendTo) {

        toAppendTo.append(getTransactionId());

       

    }

    protected String getTransactionId() {

      

       String transacationId = TransactionLogIdGenerator.myTransactionId();

      

        return transacationId;

    }

}

2. Next create TransactionIdGenerator.java class for generating TransactionLogId.

TransactionIdGenerator.java

public class TransactionLogIdGenerator {

       public static String  myTransactionId(){

              return "1234-5678-0123";

             

       }

   }

3. Now we need add custom pattern in log4j.xml file using  %trnLogid. And we have to add custom pattern plugin package name in log4j2.xml file in configuration element.

      log4j2.xml

      <?xml version="1.0" encoding="UTF-8"?>

<configuration xmlns="http://logging.apache.org/log4j/2.0/config"

       status="OFF" packages="com.custom.pattern">

       <Appenders>

    <Console name="STDOUT" target="SYSTEM_OUT">

     <PatternLayout pattern="  Date:-%d  TransactionLogID:- %trnLogid   line Number:-%L  Location:-%l   classNmae: %C  Message:-%m%n"/>

   

    </Console>

  </Appenders>

  <loggers>

              <Logger name="org.apache.log4j.xml" level="all" />

              <root level="all">

                     <appender-ref ref="STDOUT" level="TRACE" />

                     </root>

  </loggers>

</configuration>

  For testing log4j2 custom pattern we have to create one Test.java class.

Test.java

public class Test {

        private static final Logger logger = LogManager.getLogger(Test.class);   

       public static void myTest(){

              logger.info("this is my info message");

              logger.debug("This is debug message");

             

       }

       public static void main(String[] args) {

              myTest();

       }

}

The output comes like below.

Date:-2015-06-22 16:26:50,612  TransactionLogID:- 1234-5678-0123   line Number:-12  Location:-com.custom.test.Test.myTest(Test.java:12)   classNmae: com.custom.test.Test  Message:-this is my info message

Date:-2015-06-22 16:26:50,616  TransactionLogID:- 1234-5678-0123   line Number:-13  Location:-com.custom.test.Test.myTest(Test.java:13)   classNmae: com.custom.test.Test  Message:-This is debug message