Spring MVC + Log4j example

In this tutorial, we will show you how to use the log4j framework to do the logging in a Spring MVC web application.

Technologies and tools used :

• Log4j 1.2.17
• Spring 4.1.6.RELEASE
• Maven 3
• Tomcat 6
• Eclipse Kepler 4.3

Note
By default, Spring (spring-core) is using the JCL (commons-logging) for logging, and the JCL has a runtime discovery algorithm to find out for other logging frameworks in well known places on the project classpath.
To integrate log4j, all you need to do is :

Puts the log4j.jar in the project classpath.
Create a log4j.properties or log4j.xml file in the project root classpath (if you follow the Maven standard directory structure, this should be the resources folder).

1. Project Directory

Review the final project structure.

2. Project Dependencies

Declares the following dependencies :

pom.xml

    <properties>
        <spring.version>4.1.6.RELEASE</spring.version>
        <log4j.version>1.2.17</log4j.version>
    </properties>

    <dependencies>

        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- Log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>

    </dependencies>

3. log4j.properties

Create a log4j.properties file, and put it in the resources. folder, refer to the above project directory structure.

log4j.properties

# Root logger option
log4j.rootLogger=DEBUG, stdout, file

# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

# Redirect log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
#outputs to Tomcat home
log4j.appender.file.File=${catalina.home}/logs/myapp.log
log4j.appender.file.MaxFileSize=5MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

4. Spring MVC Controller + Message Logging

A simple controller to return a welcome page. Furthermore, it shows you how to use log4j to do the logging.

WelcomeController.java

package com.mkyong.common.controller;

import org.apache.log4j.Logger;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class WelcomeController {

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

    @RequestMapping(value = "/", method = RequestMethod.GET)
    public ModelAndView getWelcome() {

        //logs debug message
        if(logger.isDebugEnabled()){
            logger.debug("getWelcome is executed!");
        }

        //logs exception
        logger.error("This is Error message", new Exception("Testing"));

        ModelAndView model = new ModelAndView("welcome");
        model.addObject("msg", "Hello Spring MVC + Log4j");
        return model;

    }

}

5. Demo

5.1 Download the source code, and run the web app with the embedded Jetty container.

$ mvn jetty:run

Access URL : http://localhost:8080/spring-mvc-log4j/

5.2 All logging messages will be displayed in the console.

log4j.properties

# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

Jetty console

2015-06-19 14:10:35 DEBUG WelcomeController:19 - getWelcome is executed!
2015-06-19 14:10:35 ERROR WelcomeController:23 - This is Error message
java.lang.Exception: Testing
        at com.mkyong.common.controller.WelcomeController.getWelcome(WelcomeController.java:23)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)