By default, Spring Boot uses logback, but you can easily integrate log4j2 with Spring Boot by removing the Starter logging library and adding the Spring Boot log4j2 library. I have created a youtube video including adding JDBC Appender. The video has 5 Steps:
#1 Setup Log4j2
#2 Setup Basic properties & Log4j2.xml Configuration file
#3 Log4j2 Setup for Spring Profile
#4 Add JDBCAppender
#5 Add Custom columns
Hope it helps if you are looking to integrate log4j2 in Spring Boot.