java随机生成指定的位数

/**
     * 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 = 域名Int(域名th());
            域名nd(域名At(num));
            str = 域名ace((域名At(num)+""), "");
        }
        return 域名ring();
    }
 
    public static void main(String[] args) {

        域名tln(game(4));
    }