Spring 랜덤값 초기화

http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#boot-features-external-config-random-values

my.secret=${random.value}
my.number=${random.int}
my.bignumber=${random.long}
my.number.less.than.ten=${random.int(10)}
my.number.in.range=${random.int[1024,65536]}