generate a random alpha-numeric string using BigInteger - Java Algorithm

Java examples for Algorithm:String

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Description

generate a random alpha-numeric string using BigInteger

Demo Code




import java.math.BigInteger;
import java.security.SecureRandom;

/**/*from  ww w . j av a  2s  .  c o  m*/
 * @see <a
 *      href="http://stackoverflow.com/questions/41107/how-to-generate-a-random-alpha-numeric-string">How
 *      to generate a random alpha-numeric string?</a>
 */
public final class RandomStringGenerator
{
  public static void main(final String[] args)
  {
    final int strlen = 8;
    final int numstr = 10;

    final RandomStringGenerator strgen = new RandomStringGenerator(strlen);

    System.out
      .println(String
        .format("%s random lowercase strings, of length %d alphanumeric characters:",
                numstr,
                strlen));

    for (int i = 0; i < numstr; i++)
    {
      System.out.println(strgen.nextRandomString());
    }
  }

  private static final SecureRandom random = new SecureRandom();

  private final int length;

  public RandomStringGenerator(final int length)
  {
    if (length < 1 && length > 52)
    {
      throw new IllegalArgumentException("Length is out of bounds (1 - 52)");
    }

    this.length = length;
  }

  public String nextRandomString()
  {
    return new BigInteger(length * 5, random).toString(32);
  }

}

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