20자리 랜덤 문자열 생성 (AccessKey 만들 때)

랜덤 문자열 생성 (AccessKey 만들 때)

import java.util.Random;
public class MyClass {
    public static void main(String args[]) {
        String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
    int strLength = str.length();

    Random random = new Random();

    StringBuffer randomStr = new StringBuffer();
    for (int i = 0; i < 20; i++) {
      randomStr.append(str.charAt(random.nextInt(strLength)));
    }

    System.out.println(randomStr.toString());

    }
}