HTML Unit Help

**Seegee** · April 2nd, 2012, 05:52 PM

Hey guys, So Im trying to make a program using the HTML Unit library that will login to a site with my login info, and then go to another page of the site and post data to that page. My code, is getting null pointer exceptions, as if the form that Im trying to access does not exist. Here is the code to better understand:

    private void HitActionPerformed(java.awt.event.ActionEvent evt) {                                    
        try {
            String IP;
            String Port;
            String Time;
            IP=Host.getText();
            Port=PortField.getText();
            Time=TimeField.getText();
 
 
 
                     final WebClient webClient = new WebClient();
 
//This part of the code logs in to the site, it works fine as I get no errors on it
                    final HtmlPage page1 = webClient.getPage("http://atomicbooter.org/");
                    webClient.getCookieManager().setCookiesEnabled(true);
 
    final HtmlForm form = page1.getFirstByXPath("//form[@action='set_state.php?action=login']");
 
                    final HtmlSubmitInput button = form.getFirstByXPath("/html/body/div/div[4]/form/table/tbody/tr[3]/td[2]/input");
                    final HtmlTextInput textField = form.getInputByName("username");
                    final HtmlPasswordInput Pass = form.getInputByName("password");
 
 
                    textField.setValueAttribute("Seegee");
                    Pass.setValueAttribute("PASSWORD");
 
                    final HtmlPage page2 = button.click();
 
 
 
 
 
 
                   //This part of the code goes to the next page that I want.
                    final HtmlPage page3 = webClient.getPage("http://atomicbooter.org/hub.php");
 
        final HtmlForm form2 = page3.getFirstByXPath("/html/body/div/div[6]/form");
 
                    final HtmlSubmitInput button2 = form.getFirstByXPath("/html/body/div/div[6]/form/table/tbody/tr[6]/td/input");
                    final HtmlTextInput textField2 = form.getFirstByXPath("//*[@id=host]");
                    final HtmlTextInput tme = form.getFirstByXPath("/html/body/div/div[6]/form/table/tbody/tr[4]/td[2]/input");
                    final HtmlTextInput prt = form.getFirstByXPath("//*[@id=port]");
                    final HtmlTextInput pwr = form.getFirstByXPath("/html/body/div/div[6]/form/table/tbody/tr[5]/td[2]/input");
 
 
 
                    textField.setValueAttribute(IP);
                    tme.setValueAttribute(Time); // THIS IS LINE 194!!!!!!! WHERE I GET NULL POINTER EXCEPTION!
                    prt.setValueAttribute(Port);
                    pwr.setValueAttribute("100");
 
 
                    final HtmlPage page4 = button.click();
        } catch (IOException ex) {
            Logger.getLogger(Master.class.getName()).log(Level.SEVERE, null, ex);
        }
 
    }

This is the code without the gui, as you dont need the gui, but the gui is in the same class. Running this code returns "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Master.HitActionPerformed(Master.java:194)"

The object does exist. Here is the html source code of the second page of the site (The page that I get the error on) for you to see:

HTML Code:

<!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Transitional//EN' 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd'>
<html xmlns='http://www.w3.org/1999/xhtml' xml:lang='en' lang='en'>
<head>
<title>Atomic Booter</title>
<meta http-equiv='Content-Type' content='text/html; charset=iso-8859-1'>
<meta name='robots' content='noindex,nofollow'>
<link rel='stylesheet' type='text/css' href='css/blue.css' />
</head>
<body>
<div id='container'>
<div id='logo'>
<a href='index.php' title='Home'><img src='images/atomic.png' alt='Atomic Booter' /></a>
</div>
<div id='login'>
Welcome, <a href='profile.php?id=31' title='View My Profile'>seegee</a>!<br />
 
</div>
<div class='br'></div>
<div id='navlist'>
<ul>
<li><a href='index.php' title='Home'>Home</a></li>
<li><a href='hub.php' title='Boot' class='active'>Boot</a></li>
<li><a href='converter.php' title='Host -> IP'>Host -> IP</a></li>
<li><a href='ip_logger.php' title='IP Logger'>IP Logger</a></li>
<li><a href='friends.php' title='Friends'>Friends</a></li>
<li><a href='enemies.php' title='Enemies'>Enemies</a></li>
<li><a href='attacks.php' title='My Attacks'>My Attacks</a></li>
 
<li><br /></li>
<li><a href='profile.php?id=31' title='View Profile'>View Profile</a></li>
<li><a href='edit_profile.php' title='Edit Profile'>Edit Profile</a></li>
<li><a href='messages.php' title='Messages'>Messages</a></li>
<li><a href='statistics.php' title='Statistics'>Statistics</a></li>
<li><a href='set_state.php?action=logout' title='Logout'>Logout</a></li>
</ul>
</div>
<div class='content'>
<h3>Statistics</h3>
<form>
 
<table cellpadding='5' cellspacing='5' style='text-align: left;'>
<tr>
<td style='width: 60%; text-align: right;'>Server Count:</td>
<td>2</td>
</tr>
<tr>
<td style='text-align: right;'>Allocated Servers:</td>
<td>2</td>
</tr>
<tr>
<td style='text-align: right;'>Booter Version:</td>
<td>1.1</td>
 
</tr>
</table>
</form>
 
</div>
<div class='content'>
<h3>DDoS Attack</h3>
<form name='booter' action='' method='post'>
<center>
Use the form below to initiate an attack:</center><br />
<table cellpadding='5' cellspacing='5' style='text-align: left;'>
<tr>
<td style='text-align: right;' valign='middle'>Flood Type</td>
<td>
 
UDP And SYN</td>
</tr>
<tr>
<td style='text-align: right;'>Target</td>
<td width='50%'><input type='text' name='host' id='host' size='30' value='' /></td>
</tr>
<tr>
<td style='text-align: right;'>Port (0 For Random)</td>
<td width='50%'><input size='5' name='port' type='text' id='port' value='80'></td>    
</tr>
<tr>
<td style='text-align: right;' valign='middle'>Time:</td>
<td><input type='text' name='time' size='2' value='35' /> seconds</td>
 
</tr>
<tr>
<td style='text-align: right;' valign='middle'>Power:</td>
<td><input type='text' name='power' size='2' value='50' /> %</td>
</tr>
<tr>
<td colspan='2' valign='right' style='text-align: right;'><input type='submit' name='boot' class='button' value='Flood' /></td>
</tr>
</table>
 
</form>
</div>
<div class='br'></div>
<div id='footer'>
 
<p class='center' style='border: 1px solid #ccc; background: #111; padding: 5px; margin-bottom: 15px;'>
<b>Online Users:</b><br /><br />
<span style='font-size: 10px;'>
<a href='profile.php?id=31' title='View Profile'>seegee</a>, <a href='profile.php?id=30' title='View Profile'>neilvip1</a>, <a href='profile.php?id=42' title='View Profile'>Majin</a>, <a href='profile.php?id=116' title='View Profile'>Judahmang</a>, <a href='profile.php?id=56' title='View Profile'>xjoshgx</a>, <a href='profile.php?id=50' title='View Profile'>Citizen</a></span>
</p>
 
<p class='center'>
Copyright &copy; Atomic Booter<br />
<a href='tos.php' title='Terms Of Service' target='_blank'>Terms Of Service</a>
</p>
</div>
</div>
</body>
</html>

It would be great if someone could help. Thanks in advance!

**aussiemcgr** · April 2nd, 2012, 06:01 PM

If this:

tme.setValueAttribute(Time);

is throwing a null pointer, then this:

Time=TimeField.getText();

must be setting Time to null.
Clearly TimeField exists, otherwise you'd get an error thrown there instead. The question becomes: when does "getText() return null", which I do not know. Maybe someone else can figure it out from here.

**copeg** · April 2nd, 2012, 06:33 PM

A quick look at the API for HtmlForm states for the getFirstByXPath method:

returning the first matching element, or null if no node matches the specified XPath expression.

Thus given the location of the exception, I'd say that tme is null. I'm not familiar with how this library parses the values, but make sure you are specifying the correct values to parse, and to verify what is null use some println's (based upon the above, the first variable to test would be tme)

**Seegee** · April 2nd, 2012, 06:57 PM

Printing Time returns the value that I enter into the "TimeField" text box. Printing tme returns null, but what should it return? tme is a text box on an html page. I cant seem to figure this out :/ The only thing I can think of is that it is not keeping me logged into the site, and you need to be logged in to access the second page (hub.php) but it should keep me logged in as I have cookies enabled. Any other ideas?

**copeg** · April 2nd, 2012, 07:24 PM

Originally Posted by Seegee

Printing tme returns null

Work backwards from there. What does printing the other values from that page print? Are they null as well? If not, then your parsing of the page is incorrect. If so, then you should investigate whether the page is loaded correctly.

Just as I write the advice above, a closer look at your code - presuming I understand it correctly - suggests the variables tme, prt, pwr should be retrieved from form2?

**Seegee** · April 2nd, 2012, 07:32 PM

Printing tme, pwr, prt, or textField2 all return null. And yes, they come from the XPath inside of the () after them. That XPath is in form 2. I personally think that it is a problem with the cookies. When I disable cookies, it gives me the same exact error. On this site, if you don't have the login cookie, you wont stay logged in and it will just log you out and redirect you to the login page. I think that it is redirecting it to the login page and then java cant find the text boxes and buttons because they are not on the login page, therefore making them null.

**copeg** · April 2nd, 2012, 08:16 PM

Print out the page that the site is returning and inspect the source (I presume the API you are using has methods of doing this). That being said, what I meant by the above post:

final HtmlTextInput tme = form.getFirstByXPath("/html/body/div/div[6]/form/table/tbody/tr[4]/td[2]/input");

Do you want this to refer to form2 rather than form?

**Seegee** · April 2nd, 2012, 08:38 PM

Originally Posted by copeg

Print out the page that the site is returning and inspect the source (I presume the API you are using has methods of doing this). That being said, what I meant by the above post:

final HtmlTextInput tme = form.getFirstByXPath("/html/body/div/div[6]/form/table/tbody/tr[4]/td[2]/input");

Do you want this to refer to form2 rather than form?

God im stupid. I cant believe i didnt change form to form 2. Well anyway, that got rid of the errors but its still not working. The site is something I use to stress test servers and connections and it is not stressing the ip that I put yet when I do it from the actual site, it does. I get no output now.

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