Skip to main content

Basic Log4j tutorial

Step 1 :

create file log4j.properties in $project_home/src/

log4j.appender.portlet = org.apache.log4j.FileAppender
# log file will be in tomcat/logs/
log4j.appender.portlet.File = ${catalina.home}/logs/privatemessage.log
log4j.appender.portlet.Append = false
log4j.appender.portlet.layout = org.apache.log4j.PatternLayout
log4j.appender.portlet.layout.ConversionPattern = %d{ABSOLUTE} [%t] %-5p %-30.30c{2} %x - %m %n

# only log errors
log4j.rootCategory=WARN, portlet
# log trace messages from this package and sub packages
log4j.logger.com.cisco.project=TRACE


Step 2 :

add these lines to web.xml
<context-param>
<param-name>log4jConfigLocation</param-name>
<param-value>classpath:log4j.properties</param-value>
</context-param>

Step 3 :
Use logger in your java classes, before add log4j library to your project classpath
// add imports
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

// define
private static Log logger = LogFactory.getLog(PostLogin.class);

// use this way
logger.trace(" Begin PostLoginHook.... ");

if ( logger.isDebugEnabled() ) {
logger.debug("inside method");
}



Comments

Post a Comment

Popular posts from this blog

JPA 2 new feature @ElementCollection explained

@ElementCollection is new annotation introduced in JPA 2.0, This will help us get rid of One-Many and Many-One shitty syntax. Example 1: Stores list of Strings in an Entity @Entity public class Users implements Serializable {     private static final long serialVersionUID = 1L;     @Id     @GeneratedValue(strategy = GenerationType.AUTO)     private Long id;     @ElementCollection     private List<String> certifications = new ArrayList <String> ();     public Long getId() {         return id;     }     public void setId(Long id) {         this.id = id;     }     public List <String> getCertifications() {         return certifications;     }     pub...
21 comments
Read more

Access multiple Databases in JPA

According to JPA specification we can define multiple "persistence-unit" elements (i.e. like below) in persistence.xml file and can easily refer them inside Dao layers as this. public class PolarDaoImpl {     @PersistenceContext(unitName="PolarPU")     protected EntityManager entityManager; -- } public class BearDaoImpl {     @PersistenceContext(unitName="BearPU")     protected EntityManager entityManager; -- } Checkout sample persistence.xml <?xml version="1.0" encoding="UTF-8"?> <persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">     <!-- Database 1 -->     <persistence-unit name="PolarPU" transaction-type="RESOURCE_LOCAL">        ...
3 comments
Read more

Validating CSV Files

What is CsvValidator ?   A Java framework which validates any CSV files something similar to XML validation using XSD. Why should I use this ?   You don't have to use this and in fact its easy to write something your own and also checkout its source code for reference. Why did I write this ?   Some of our projects integrate with third party application which exchanges information in CSV files so I thought of writing a generic validator which can be hooked in multiple projects or can be used by QA for integration testing. What is the license clause ?   GNU GPL v2 Are there any JUnit test cases for me checkout ?  Yes,  source How to integrate in my existing project ? Just add the Jar which can be downloaded from here  CsvValidator.jar  and you are good. Instantiate  CsvValidator c onstructor which takes these 3 arguements          // filename is the the file to be validated and here ...
7 comments
Read more