怎么获取这个rand_num

Question

求教一下啊
 http://nb.163.com/cgi-bin/vipbar/showimage.py?rand_num=0.2117899715202149
怎么获取这个rand_num

Answer 1

理论上说轻易获取不了，当然这是相当不轻易。因为理论上说Python产生的是伪随机数序列，既然是这样，就可以获取这个序列，当然，这是理论而以，现代的伪随机数算法配合使用环境，已经可以在工程上当作真正的随机数使用了。既然是随机数，如果你能预测，那么你可以去买彩票了。因为彩票就是人类试图预测随机数的一个生动案例。

Answer 2

温州-星星(42095900)  11:16:33
public static CookieContainer myCookieContainer;      
private void bgetcode_Click(object sender, EventArgs e)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(" http://nb.163.com/cgi-bin/vipbar/showimage.py?");
            request.CookieContainer = myCookieContainer;
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            response.Cookies = myCookieContainer.GetCookies(request.RequestUri);
            //获取一个包含url的Cookie集合的CookieCollection      
            Stream responseStream = response.GetResponseStream();
            //Stream responseStream = ((HttpWebResponse)request.GetResponse()).GetResponseStream();
            Image original = Image.FromStream(responseStream);
            Bitmap bitMap = new Bitmap(original);
            this.pictureBox1.Image = bitMap;           //注意：替换为你的PictureBox控件名字
            responseStream.Close();
        }
 private void topost()
        {
                        string code = tbyzm.Text.ToString();
            ArrayList list1 = new ArrayList();
            CookieContainer cookie = new CookieContainer();
            string postdate = "act=userlogin&[email protected]&password=stst123456&authcode=" + code;
            string posturl = " http://nb.163.com/cgi-bin/vipbar/login.py";
            //list1=PostData(postData, postUrl, cookie);            ASCIIEncoding encoding = new ASCIIEncoding();            byte[] data = encoding.GetBytes(postdate);
            HttpWebRequest myrequeat = (HttpWebRequest)WebRequest.Create(posturl);
            myrequeat.CookieContainer = myCookieContainer;
            myrequeat.Method = "POST";
            myrequeat.ContentType = "application/x-www-form-urlencoded";
            myrequeat.ContentLength = data.Length;
            myrequeat.Accept = "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-ms-application, application/x-ms-xbap, application/vnd.ms-xpsdocument, application/xaml+xml, */*";
            Stream newStream = myrequeat.GetRequestStream();
            // Send the data.
            newStream.Write(data, 0, data.Length);    //写入参数
            newStream.Close();            HttpWebResponse response2 = (HttpWebResponse)myrequeat.GetResponse();
            response2.Cookies = myCookieContainer.GetCookies(myrequeat.RequestUri); 
            StreamReader sr2 = new StreamReader(response2.GetResponseStream(), Encoding.UTF8);
            recievedate = sr2.ReadToEnd();
            textBox1.Text = recievedate;
这样有什么问题的吗？