Log4j 2 provides simple solution to the integration of logging to the web applications. If you run servlet 3.0 web application, then there is no need for any configurations. The log4j context is initialized at the time of loading the web application. If you run the servlet 2.5 web application, there is configuration parameters to be added in the web.xml deployment descriptor to enable the logging. This tutorial explain the simple integration of Log4j 2 and Spring integration.
Note that, log4j 2 doesn’t support the servlet 2.4 and prior web applications. This tutorial explains how to integrate log4j 2 with the simple Spring MVC application.
HelloController.java
[code lang=”java”]
package javabeat.net.controller;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
@RequestMapping("/welcome")
public class HelloController {
static final Logger logger = LogManager.getLogger(HelloController.class.getName());
@RequestMapping(method = RequestMethod.GET)
public String printWelcome(ModelMap model) {
logger.info("Spring MVC Log4j!");
model.addAttribute("message", "Spring 3 MVC Hello World");
return "hello";
}
}
[/code]
log4j2.java
Add the log4j2.xml in the classpath. To make it simple, add this file to the root of your source code package.
[code lang=”xml”]
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO">
<Appenders>
<Console name="CONSOLE" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} – %msg%n" />
</Console>
</Appenders>
<Loggers>
<logger name="javabeat.net.controller" level="INFO" />
</Loggers>
</Configuration>
[/code]
hello.jsp
[code lang=”xml”]
<html>
<body>
Message : ${message}
</body>
</html>
[/code]
springmvc-servlet.xml
[code lang=”xml”]
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:component-scan base-package="javabeat.net.controller" />
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/jsp/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
</beans>
[/code]
web.xml
In the deployment descriptor, you have to add listener and filter to enable the logging.
[code lang=”xml”]
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="WebApp_ID" version="2.5">
<display-name>SpringMVC</display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<listener>
<listener-class>org.apache.logging.log4j.core.web.Log4jServletContextListener</listener-class>
</listener>
<filter>
<filter-name>log4jServletFilter</filter-name>
<filter-class>org.apache.logging.log4j.core.web.Log4jServletFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>log4jServletFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
<dispatcher>FORWARD</dispatcher>
<dispatcher>INCLUDE</dispatcher>
<dispatcher>ERROR</dispatcher>
</filter-mapping>
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
[/code]
Output…
If you run the above program, you would get the output message as below.
[code]
16:44:19.732 [http-8080-1] INFO javabeat.net.controller.HelloController – Spring MVC Log4j!
[/code]