Java生成隨機密碼

public class RandomString {


      public static String randomstring(int lo, int hi){
              int n = rand(lo, hi);
              byte b[] = new byte[n];
              for (int i = 0; i < n; i++)
                      b[i] = (byte)rand('a', 'z');
              return new String(b, 0);
      }

      private static int rand(int lo, int hi){
                  java.util.Random rn = new java.util.Random();
              int n = hi - lo + 1;
              int i = rn.nextInt(n);
              if (i < 0)
                      i = -i;
              return lo + i;
      }

      public static String randomstring(){
              return randomstring(5, 25);
      }

    /**
     * @param args
     */
    public static void main(String[] args) {
            System.out.println(randomstring());

    }


}</pre>