What logger does Spring Boot use?

ghz 9months ago ⋅ 63 views

Spring Boot uses the SLF4J (Simple Logging Facade for Java) as the logging facade and allows you to plug in various logging implementations underneath SLF4J. By default, Spring Boot includes Logback as the logging implementation, although you can easily switch to other implementations like Log4j 2 or Java Util Logging (JUL) by adding the appropriate dependencies to your project and configuring them.

SLF4J serves as a bridge between your application code and the underlying logging framework, providing a unified API for logging while allowing you to swap out the actual logging implementation without changing your application code. This makes it easier to manage logging in your Spring Boot application and provides flexibility in choosing the logging framework that best fits your requirements.

To include Logback in your Spring Boot project, you don't need to add any additional dependencies explicitly because it's already included as a transitive dependency of the Spring Boot starter dependencies. However, if you prefer to use a different logging implementation like Log4j 2 or JUL, you can exclude Logback and include the desired logging dependency in your pom.xml or build.gradle file.

Here's an example of excluding Logback and including Log4j 2 in a Maven project:

<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>

With this configuration, Spring Boot will use Log4j 2 as the logging implementation instead of Logback. Similarly, you can include dependencies for other logging implementations like JUL if needed.

Remember to configure the logging framework according to your application's requirements by providing configuration files such as logback.xml for Logback or log4j2.xml for Log4j 2.

#spring