/**

     * 获取count个随机数

     * @param count 随机数个数

     * @return

     */

    public static String game(int count){

        StringBuffer sb = new StringBuffer();

        String str = "0123456789";

        Random r = new Random();

        for(int i=0;i<count;i++){

            int num = r.nextInt(str.length());

            sb.append(str.charAt(num));

            str = str.replace((str.charAt(num)+""), "");

        }

        return sb.toString();

    }

    public static void main(String[] args) {

        System.out.println(game(4));

    }