Logging with Spring Boot - Logback, SLF4j and LOG4j2


Image


CHECK OUT OUR 8 AMAZING AWS CERTIFICATION COURSES HERE


Learn how to log effectively with Spring Boot. We will look at Spring Boot Starter for Logging. We will look at the defaults in Spring Boot for Logging - Logback and SLF4J. We will also looking at the Spring Boot starter for log4j2.

Free Courses - Learn in 10 Steps

Default Logging Framework with Spring Boot

Spring boot provides a default starter for logging - spring-boot-starter-logging. It is included by default in spring-boot-starter which is included in all other starters.

This means whenever you use any starters like spring-boot-starter-web or spring-boot-starter-data-jpa, you get logging for free!

Let’s look at what is present in the Logging Starter.

<dependency>
  <groupId>ch.qos.logback</groupId>
  <artifactId>logback-classic</artifactId>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.apache.logging.log4j</groupId>
  <artifactId>log4j-to-slf4j</artifactId>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>jul-to-slf4j</artifactId>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>log4j-over-slf4j</artifactId>
  <scope>compile</scope>
</dependency>

As you can see the default logging framework is Logback with SLF4j as implementation.

By default, all logging goes to console.

Configure Logging Levels

In application.properties, we can use the “logging.level” prefix to set logging levels.

logging.level.some.package.path=DEBUG
logging.level.some.other.package.path=ERROR

Root logging level can be configured as shown below

logging.level.root=WARN

Configuring a Log File

You can configure a log file by using logging.file property in application.properties. The logging here would be in addition to the logging in console.

logging.file=\path_to\logfile.log

Custom configuration using logback.xml

Spring Boot will pick up all custom configuration using logback.xml as long as it is in the application class path.

Example code

LOGGER.trace("Your log - {}", value);
LOGGER.debug("debug - {}", value);
LOGGER.info("info- {}", value);          
LOGGER.warn("warn - {}", value);          
LOGGER.error("error - {}", value);

Using Log4j2 for logging with Spring Boot

We would need to exclude the dependency on spring-boot-starter-logging and add a dependency on spring-boot-starter-log4j2.

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>

Let’s take a quick look at the dependencies in log4j2 starter.

<dependency>
  <groupId>org.apache.logging.log4j</groupId>
  <artifactId>log4j-slf4j-impl</artifactId>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.apache.logging.log4j</groupId>
  <artifactId>log4j-api</artifactId>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.apache.logging.log4j</groupId>
  <artifactId>log4j-core</artifactId>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>jul-to-slf4j</artifactId>
  <scope>compile</scope>
</dependency>

Custom configuration using log4j2.xml

Spring Boot will pick up all custom configuration using log4j2.xml as long as it is in the application class path.

You also have the option of using YAML or JSON with Log4j2.

  • YAML - log4j2.yaml or log4j2.yml
  • JSON - log4j2.json or log4j2.jsn

However, you would need to include the appropriate dependency to handle yaml(jackson-dataformat-yaml) or json(jackson-databind).

8 AWS Certification Courses

We are releasing courses for 3 Certifications under 3 categories - STEP BY STEP, EXAM REVIEW and PRACTICE TESTS:

  • Step by Step courses are for you if you are getting started with AWS
  • Exam Review courses help you to quickly review for the exam in a few hours
  • Practice Tests help you to test your preparation - How ready are you for the exam?

STEP BY STEP COURSES: ZERO AWS KNOWLEDGE? Start your journey now!

EXAM REVIEW COURSES: You prepare for the exam for 1-6 months. How do you remember everything you studied? Review for the exam in under 6 HOURS using this crash courses!

PRACTICE TESTS: Test yourselves for the certification exam with our practice tests

Best Selling Udemy Courses

Image
Image Image Image Image Image Image Image Image Image Image Image

Join 450,000 Learners and 30+ Amazing Courses

350,000 Learners are learning everyday with our Best Selling Courses : Spring Boot Microservices, Spring, Spring Boot, Web Services, Hibernate, Full Stack React, Full Stack Angular, Python, Spring Interview Guide, Java Interview, Java Functional Programming, AWS, Docker, Kubernetes, PCF, AWS Fargate and Azure


Do not know where to start your learning journey? Check out our amazing learning paths:
Learning Path 01 - Spring and Spring Boot Web Applications and API Developer,
Learning Path 02 - Full Stack Developer with Spring Boot, React & Angular,
Learning Path 03 - Cloud Microservices Developer with Docker and Kubernetes,
Learning Path 04 - Learn Cloud with Spring Boot, AWS, Azure and PCF and
Learning Path 05 - Learn AWS with Microservices, Docker and Kubernetes


Subscribe

FREE COURSES



Related Posts

Understanding jwt token

Let us understand the json web tokens

Single sign-on workflow

Let us understand the single sign-on workflow

Oauth2.0 - Resource Owner Password Credentials grant workflow

Let us understand the Oauth2.0 Resource Owner Password Credentials grant workflow

Oauth2.0 - Implicit grant workflow

Let us understand the Oauth2.0 implicit grant workflow

Oauth2.0 - Client Credentials grant workflow

Let us understand the Oauth2.0 client credentials grant workflow

Oauth2.0 - Authorization grant workflow

Let us understand the Oauth2.0 authorization grant workflow

Writing Integration Tests for Rest Services with Spring Boot

Setting up a basic REST Service with Spring Boot is a cake walk. We will go one step further and add great integration tests!

Integrating Spring Boot and Spring JDBC with H2 and Starter JDBC

Learn using Spring Boot Starter JDBC to connect Spring Boot to H2 (in memory database) using Spring JDBC. You will create a simple project with Spring Boot. You will add code to the project to connect to a database using Spring JDBC. You will learn to implement the basic CRUD methods.

JUnit Tutorial for Beginners in 5 Steps

JUnit Tutorial for Beginners in 5 Steps. Setting up a basic JUnit example and understanding the basics of junit.

JPA and Hibernate Tutorial For Beginners - 10 Steps with Spring Boot and H2

JPA and Hibernate in 10 Steps with H2 - Setting up a basic project example with Spring Boot and in memory database H2. Its a cake walk.


Search