class path resource [] cannot be resolved to absolute file path because it does not reside in the file system: jar:file:/app/app.jar!/BOOT-INF/classes!/
 

mapper-locations: classpath:com/mysql/*.xml,classpath:com/postgresql/*.xml

mapper-locations: classpath*:com/mapper/**/*.xml

classpath: = only root classpath
classpath*: = scan all JARs + subfolders