獲取隨機不重複字符串

/**
 * 獲取隨機不重複字符串
 */
public static String createId()
{
   String id = UUID.randomUUID().toString();

   id = dekHash(id) + "";

   int diff = 12 - id.length();
   String randStr = RandomStringUtils.randomAlphabetic(12);
   for (int i = 0; i < diff; i++)
   {
      int randIndex = (int) (Math.random() * randStr.length());
      int index = (int) (Math.random() * id.length());
      id = id.substring(0, index) + randStr.charAt(randIndex) + id.substring(index, id.length());
   }
   return id+(int)(Math.random()*1000);
}

 

private static int dekHash(String str)
{
   int hash = str.length();

   for (int i = 0; i < str.length(); i++)
   {
      hash = ((hash << 5) ^ (hash >> 27)) ^ str.charAt(i);
   }

   return (hash & 0x7FFFFFFF);
}