package xyz.zhouxy.plusone.commons.util; import java.security.SecureRandom; public final class RandomTools { private RandomTools() { throw new IllegalStateException("Utility class"); } public static String secureRandomStr(char[] sourceCharacters, int length) { SecureRandom random = new SecureRandom(); char[] result = new char[length]; for (int i = 0; i < length; i++) { result[i] = sourceCharacters[random.nextInt(sourceCharacters.length)]; } return String.valueOf(result); } }