随机生成字符串

public String make()
      {
          // author : herrapfel
          String radStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
          StringBuffer generateRandStr = new StringBuffer();
          Random rand = new Random();
          int length = 32;
          for(int i=0;i<length;i++)
          {
              int randNum = rand.nextInt(36);
              generateRandStr.append(radStr.substring(randNum,randNum+1));
          }
          return generateRandStr+"";
      }