Spring Boot: How can I set the logging level with application.properties?

With Springboot 2 you can set the root logging Level with an Environment Variable like this:

logging.level.root=DEBUG

Or you can set specific logging for packages like this:

logging.level.my.package.name=TRACE

According to the documentation you can have different logging levels based on java packages.

 logging.level.com.mypackage.myproject=WARN
 logging.level.org.springframework=DEBUG
 logging.level.root=INFO 

This would mean that

• For your custom package com.mypackage.myproject WARN logging level would be applied
• For spring framework package org.springframework DEBUG logging level would be applied
• For every other package INFO logging level would be applied

You can also group together different java packages and instruct the system to use the same logging level for all packages of the group in a single line.

In the previous example you could do

 logging.level.root=INFO 
 logging.level.org.springframework=DEBUG
 
 logging.group.myCustomGroup = com.mypackage.myproject, com.otherpackage.otherproject, com.newpackage.newproject
 logging.level.myCustomGroup=WARN

This would mean that the packages

• com.mypackage.myproject
• com.otherpackage.otherproject
• com.newpackage.newproject

would all have logging level WARN applied

You can try setting the log level to DEBUG it will show everything while starting the application

logging.level.root=DEBUG

logging:
  level:
    root: INFO
    com.mycompany.myapp: DEBUG

Existing answers are greats. I just want to share with you a new spring boot feature allowing to group logs and set logging level on the whole group.

Exemple from the docs :

• Create a logging group

logging.group.tomcat=org.apache.catalina, org.apache.coyote, org.apache.tomcat

• Set the logging level for group

logging.level.tomcat=TRACE

It's nice feature which brings more flexibility.

We can also turn on DEBUG log via command line like below:-

java -jar <jar file> --debug

in spring boot project we can write logging.level.root=WARN but here problem is, we have to restart again even we added devtools dependency, in property file if we are modified any value will not autodetectable, for this limitation i came to know the solution i,e we can add actuator in pom.xml and pass the logger level as below shown in postman client in url bar http://localhost:8080/loggers/ROOT or http://localhost:8080/loggers/com.mycompany and in the body you can pass the json format like below

{
  "configuredLevel": "WARN"
}

In my current config I have it defined in application.yaml like that:

logging:
  level:
    ROOT: TRACE

I am using spring-boot:2.2.0.RELEASE. You can define any package which should have the TRACE level like that.