Integrate Log4j2 to Java Spring

#java #spring #log4j

Is recomended see this link.

Add this exclusion to the following packages (the dependencies you have)

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
        </exclusion>
    </exclusions>
</dependency>

This dependencies are new

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.9.0</version>
</dependency>
<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter</artifactId>
    <version>5.8.2</version>
    <scope>test</scope>
</dependency>

Create the web.xml file at webapp\WEB-INF, create webapp folder under src\main

This is a web.xml example

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
    <context-param>
        <param-name>isLog4jAutoInitializationDisabled</param-name>
        <param-value>true</param-value>
    </context-param>
    <context-param>
        <param-name>log4jContextName</param-name>
        <param-value>exampleLogFolderName</param-value>
    </context-param>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>swagger-ui.html#</welcome-file>
    </welcome-file-list>
</web-app>

Below resource generate the log4j2.xml file

Here's a example file

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="30">
    <Properties>
        <Property name="LOG_PATTERN">
            %d{yyyy-MM-dd HH:mm:ss.SSS} %5p ${hostName} --- [%15.15t] %-40.40c{1.} : %m%n%ex
        </Property>
    </Properties>
    <Appenders>
        <Console name="ConsoleAppender" target="SYSTEM_OUT" follow="true">
            <PatternLayout pattern="${LOG_PATTERN}"/>
        </Console>
        <RollingFile name="FileAppender" fileName="logs/testProject/log4j2-.log"
                     filePattern="logs/test/log4j2-%d{yyyy-MM-dd}-%i.log">
            <PatternLayout>
                <Pattern>${LOG_PATTERN}</Pattern>
            </PatternLayout>
            <Policies>
                <SizeBasedTriggeringPolicy size="3MB" />
            </Policies>
            <DefaultRolloverStrategy max="30"/>
        </RollingFile>
    </Appenders>
    <Loggers>
        <Logger name="com.test.TestProject" level="debug" additivity="false">
            <AppenderRef ref="ConsoleAppender"/>
            <AppenderRef ref="FileAppender"/>
        </Logger>

        <Root level="info">
            <AppenderRef ref="ConsoleAppender"/>
            <AppenderRef ref="FileAppender"/>
        </Root>
    </Loggers>
</Configuration>