Spring MVC + Logback SLF4j example

In this tutorial, we will show you how to setup slf4j and logback in a Spring MVC web application.

Technologies used :

1. Spring 4.1.6.RELEASE
2. Logback 1.1.3
3. Maven 3 or Gradle 2.0
4. Tomcat 7
5. Eclipse 4.4

To setup logback framework you need to :

1. Exclude commons-logging from spring-core
2. Bridge the Spring’s logging from JCL to SLF4j, via jcl-over-slf4j
3. Include logback as dependency
4. Create a logback.xml in the src/main/resources folder
5. Done

1. Build Tools

1.1 For Maven

    <properties>
	<jdk.version>1.7</jdk.version>
	<spring.version>4.1.6.RELEASE</spring.version>
	<logback.version>1.1.3</logback.version>
	<jcl.slf4j.version>1.7.12</jcl.slf4j.version>
    </properties>
    <dependencies>
	<!-- 1. exclude commons-logging -->
	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-core</artifactId>
		<version>${spring.version}</version>
		<exclusions>
		  <exclusion>
			<groupId>commons-logging</groupId>
			<artifactId>commons-logging</artifactId>
		  </exclusion>
		</exclusions>
	</dependency>
	<dependency>
		<groupId>org.springframework</groupId>
		<artifactId>spring-webmvc</artifactId>
		<version>${spring.version}</version>
	</dependency>
	<!- 2. Bridge logging from JCL to SLF4j-->
	<dependency>
		<groupId>org.slf4j</groupId>
		<artifactId>jcl-over-slf4j</artifactId>
		<version>${jcl.slf4j.version}</version>
	</dependency>
	<!-- 3. logback -->
	<dependency>
		<groupId>ch.qos.logback</groupId>
		<artifactId>logback-classic</artifactId>
		<version>${logback.version}</version>
	</dependency>
    <dependencies>

1.2 For Gradle

apply plugin: 'java'
apply plugin: 'war'
apply plugin: 'eclipse-wtp'
repositories {
    mavenCentral()
//1. exclude commons-logging
configurations.all {
   exclude group: "commons-logging", module: "commons-logging"
dependencies {
 	//2. bridge logging from JCL to SLF4j
 	compile 'org.slf4j:jcl-over-slf4j:1.7.12'
	//3. Logback
	compile 'ch.qos.logback:logback-classic:1.1.3'
	compile 'org.springframework:spring-webmvc:4.1.6.RELEASE'

2. Project Directory

Create a logback.xml in the src/main/resources folder

3. logback.xml

This logback.xml will send all logs to console.

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
	    <layout class="ch.qos.logback.classic.PatternLayout">
		<Pattern>
			%d{yyyy-MM-dd HH:mm:ss} %-5level %logger{36} - %msg%n
		</Pattern>
	    </layout>
	</appender>
	<logger name="org.springframework" level="debug" additivity="false">
		<appender-ref ref="STDOUT" />
	</logger>
	<logger name="com.mkyong.helloworld" level="debug" additivity="false">
		<appender-ref ref="STDOUT" />
	</logger>
	<root level="error">
		<appender-ref ref="STDOUT" />
	</root>
</configuration>

For other appenders (log output), like logs to a file, please visit this log.xml examples, or this logback appender guide

4. Logback Example

package com.mkyong.common.controller;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class WelcomeController {
	private static final Logger logger = 
		LoggerFactory.getLogger(WelcomeController.class);
	@RequestMapping(value = "/", method = RequestMethod.GET)
	public String welcome(Model model) {
		logger.debug("welcome() is executed, value {}", "mkyong");
		logger.error("This is Error message", new Exception("Testing"));
		model.addAttribute("msg", "Hello Spring MVC + Logback");
		return "welcome";

5. Demo

Download the source code, and run it with Maven or Gradle.

5.1 Maven

mvn jetty:run

5.2 Gradle

gradle jettyRun

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

...
2015-06-19 21:53:33 DEBUG o.s.web.servlet.DispatcherServlet - Initializing servlet 'hello-dispatcher'
2015-06-19 21:53:33 DEBUG o.s.w.c.s.StandardServletEnvironment - Adding [servletConfigInitParams] PropertySource with lowest search precedence
2015-06-19 21:53:33 DEBUG o.s.w.c.s.StandardServletEnvironment - Adding [servletContextInitParams] PropertySource with lowest search precedence
2015-06-19 21:53:33 DEBUG o.s.w.c.s.StandardServletEnvironment - Adding [jndiProperties] PropertySource with lowest search precedence
2015-06-19 21:53:33 DEBUG o.s.w.c.s.StandardServletEnvironment - Adding [systemProperties] PropertySource with lowest search precedence
2015-06-19 21:53:33 DEBUG o.s.w.c.s.StandardServletEnvironment - Adding [systemEnvironment] PropertySource with lowest search precedence
2015-06-19 21:53:33 DEBUG o.s.w.c.s.StandardServletEnvironment - Initialized StandardServletEnvironment with PropertySources 
[servletConfigInitParams,servletContextInitParams,jndiProperties,systemProperties,systemEnvironment]
Jun 19, 2015 9:53:33 PM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring FrameworkServlet 'hello-dispatcher'
20
...
2015-06-19 21:53:45 DEBUG o.s.b.f.s.DefaultListableBeanFactory - Returning cached instance of singleton bean 'welcomeController'
2015-06-19 21:53:45 DEBUG o.s.web.servlet.DispatcherServlet - Last-Modified value for [/spring-mvc-logback/] is: -1
2015-06-19 21:53:45 ERROR c.m.c.controller.WelcomeController - This is Error message
java.lang.Exception: Testing
	at com.mkyong.common.controller.WelcomeController.welcome(WelcomeController.java:21) [WelcomeController.class:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_65]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.7.0_65]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.7.0_65]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.7.0_65]
...

Both Spring and web application logging will be sent to the console.

References

1. Spring official guide – logging
2. Logback official website
3. logback.xml examples
4. Spring MVC + Log4j