랜덤 함수 사용 ( Maven )

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.4</version>
</dependency>
 

선언....

 

로 기존에 만들어진 API를 사용하면 된다.

RandomStringUtils.randomAlphanumeric(4);

알파벳 + 숫자 를 랜덤하게 4개 뽑아준다..