For Spring Boot 2.1 and below use
logging.level.org.springframework.web=DEBUG
spring.http.log-request-details=true
For Spring Boot 2.2 and above spring.http.log-request-details has been deprecated so use
logging.level.org.springframework.web=DEBUG
spring.mvc.log-request-details=true
in your application.properties if you want to see loggingRequestDetails.
From the documentation:
Whether logging of (potentially sensitive) request details at DEBUG
and TRACE level is allowed.