In a series of posts on Logback, I’ve also discussed how to configure Logback using XML and Groovy. The posts are available as Logback Configuration: using XML<\/a> and Logback Configuration: using Groovy<\/a>.<\/p>\n\n\n\n In this post, I\u2019ll discuss how to use Logback with Spring Boot. While there are a number of logging options for Java, the Spring Boot chose to use Logback for the default logger. Like many things in Spring Boot, Logback, by default, gets configured with sensible defaults. <\/p>\n\n\n\n Logback, and most Java logging frameworks has 5 log levels:<\/p>\n\n\n\n When a log level is selected, the selected log level and all higher log levels will produce output.<\/p>\n\n\n\n The log level can be set at the root, package segment, and class level The log level will be inherited up this chain. If you set a log level for a package segment, the log level will apply to all classes under that segment.<\/p>\n\n\n\n For example, if we set the log level on the package SLF4J uses the Facade Design Pattern to provide an abstraction to popular Java logging frameworks. <\/p>\n\n\n\n Spring Boot uses SLF4J to allow for the easy configuration of alternate logging frameworks. Spring Boot starter artifacts include the SLF4J binding to Logback, and the Logback implementation.<\/p>\n\n\n\n When developing your Spring Boot Application, for logging, you will wish to use the SLFJ4 components, and NOT the logback components directly.<\/p>\n\n\n\n Should you ever wish to use a different logging implementation, you will be able to change without updating your application code.<\/p>\n\n\n\n To follow this tutorial, you can create a new Spring Boot project using the Spring Initializr. <\/p>\n\n\n\n Add the following dependencies:<\/p>\n\n\n\n You can also find this project in my Github repository here<\/a>.<\/p>\n\n\n\n We can examine the Maven dependency tree to see the dependencies the Spring Boot starter is adding to the project.<\/p>\n\n\n\n Here we can see the Spring Boot starter for Spring MVC (web) brings in the Spring Boot starter for logging. Under this dependency we can the the dependencies for Logback. Logback itself implements the binder for SLF4J, and includes the SLF4J API.<\/p>\n\n\n\n Add the following Spring MVC controller to your Spring Boot project.<\/p>\n\n\n\nLog Levels<\/h1>\n\n\n\n
Available Log Levels<\/h2>\n\n\n\n
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trace<\/code> – Detailed, fine grained, messages from program execution<\/li>\n\n\n\ndebug<\/code> – Messages intended to help debug program execution<\/li>\n\n\n\ninfo<\/code> – informational messages, often some type of event to record<\/li>\n\n\n\nwarn <\/code>– A warning message about an unusual condition<\/li>\n\n\n\nerror<\/code> – Message that an unexpected error occured.<\/li>\n<\/ul>\n\n\n\nLog Level Selection<\/h2>\n\n\n\n
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trace<\/code> enabled – trace<\/code>, debug<\/code>, info<\/code>, warn<\/code> and error<\/code> produce log output.<\/li>\n\n\n\ndebug<\/code> enabled – debug<\/code>, info<\/code>, warn<\/code> and error<\/code> produce log output.<\/li>\n\n\n\ninfo<\/code> enabled – info<\/code>, warn<\/code> and error<\/code> produce log output.<\/li>\n\n\n\nwarn<\/code> enabled – warn<\/code> and error<\/code> produce log output.<\/li>\n\n\n\nerror<\/code> enabled – Only error<\/code> produces log output.<\/li>\n<\/ul>\n\n\n\nLog Level Inheritance <\/h2>\n\n\n\n
guru.springframework.controllers<\/code> to debug<\/code> all classes in guru.springframework.controllers<\/code> and classes in any sub-packages will have their log level set to debug<\/code>.<\/p>\n\n\n\nLog Level Inheritance Examples<\/h3>\n\n\n\n
Logger<\/strong><\/td> Assigned Level<\/strong><\/td> Inherited Level<\/strong><\/td><\/tr> root<\/code><\/td>info<\/code><\/td>info<\/code><\/td><\/tr>guru<\/code><\/td>none<\/td> info<\/code><\/td><\/tr>guru.springframework<\/code><\/td>none<\/td> info<\/code><\/td><\/tr>guru.springframework<\/code>.controllers<\/td>none<\/td> info<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nLogger<\/strong><\/td> Assigned Level<\/strong><\/td> Inherited Level<\/strong><\/td><\/tr> root<\/code><\/td>warn<\/code><\/td>warn<\/code><\/td><\/tr>guru<\/code><\/td>none<\/td> warn<\/code><\/td><\/tr>guru.springframework<\/code><\/td>debug<\/code><\/td>debug<\/code><\/td><\/tr>guru.springframework<\/code>.controllers<\/td>none<\/td> debug<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Logger<\/strong><\/td> Assigned Level<\/strong><\/td> Inherited Level<\/strong><\/td><\/tr> root<\/code><\/td>error<\/code><\/td>error<\/code><\/td><\/tr>guru<\/code><\/td>none<\/td> error<\/code><\/td><\/tr>guru.springframework<\/code><\/td>info<\/code><\/td>info<\/code><\/td><\/tr>guru.springframework<\/code>.controllers<\/code><\/td>none<\/td> info<\/td><\/tr> guru.springframework<\/code>.controllers.IndexController<\/code><\/td>trace<\/code><\/td>trace<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nSLF4J – Simple Logging Facade for Java<\/h1>\n\n\n\n
Spring Boot Logback Example<\/h1>\n\n\n\n
Initial Setup<\/h2>\n\n\n\n
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Dependencies<\/h3>\n\n\n\n
![\"logback](\"https:\/\/springframework.guru\/wp-content\/uploads\/2016\/04\/Screenshot-2024-10-17-at-2.01.17\u202fPM.png\")
<\/a><\/figure>\n\n\n\nCreating Logback Loggers<\/h2>\n\n\n\n