How to programmatically send a HTTP request with p

Question

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• How to use java.net.URLConnection to fire and handle HTTP requests 11 answers

If I use a browser to send information to the server (for example using a log-in, password page), I just fill the user text-box and the password text-box and clicking on the log-in button.

I would like to send this information but without having to use the browser. I would like to 'fill' the text-boxes but without having to do it manually in the browser. May be using a Servlet.

My question is: How to send information in text-boxes, for example, to a website, doing it from a Servlet?

Answer 1

Just in case anyone is interested, there is a plugin for Firefox called Tamper data. With it you can stop the sending of and http request and modify it. It will show you the "url" you need for sending the params, the values they currently have, and their name. You can check it out here. After that you can use a request.sendRedirect('url you got from Tamper Data');

Answer 2

It is not clear to me what you really up to. I assume that the servlet will be the one who will send the data. Here some examples.

Using setAttribute then Forward the request

//On your servlet
request.setAttibute('user', 'admin');
request.setAttribute('password', '123');
getServletContext().getRequestDispatcher("page.jsp").forward(request, response);

//On your jsp page get the value using EL
<span>${user}</span>

Using session

 //On your servlet
HttpSession session = request.getSession(true);
session.setAttribute('user', 'admin');
session.setAttribute('password', '123');
getServletContext().getRequestDispatcher("page.jsp").forward(request, response);

//On your jsp page get the value using EL
<span>${user}</span>    

The above example is intended to work within the web application. To send information to another web application, which expecting a request. See sample below.

//On your jsp or servlet, you can also do the same within web application
request.sendRedirect('http://example.com?user=admin&password=123');

//on your jsp @example.com
<span>${param.user}</span>

If this is not what you mean, adding more details will be a help.

Answer 3

why not just make a call to the URL from Java using a URL like http://your.domain.name/your/servlet/path?userFieldName=THE_VALUE_YOU_WANT_TO_PASS&passwdFieldName=PASSWORD

The servlet will feel like the values are coming from those boxes.

Or you may want to dive into Apache HTTP Client to mimick a request sent from an client.

uh..oh.. are you doing functional testing? Why not look into JMeter?

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Updates as per comment

You need to know what actually form submission does? It basically forms a query string composed of Key-Values (KV) pair.

So, if you have a a text field named tfield where user has typed some text, and there is a drop down named, ddfield where user has selected optionX which has value optionX-Val. And this form gets submitted to a URL, http://my.domain.name/my/servlet -- the browser will send a request which will look like

http://my.domain.name/my/servlet?tfield=some%20text&ddfield=optionX-Val

If you want to mimic form submission, you will have to manually create a URL that has a request string containing all the fields and their values as FIELD_NAME=FIELDVALUE ordered pair separated by ampersand (&)

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ah, great idea. If you use Firebug (a Firefox extension), open the NET panel in Firebug, make a manual submission of the form that you wanted to mimic. See what request is posted when you submitted the form. It will have exact URL format that you are after. Copy this URL, replace the values and make fake submissions as much as you want.

Hope this helps.

Answer 4

a servlet takes care of the other end: it's basically a handler for http requests that lives inside a servlet container. If I understand you correctly, you're wanting to send an http request. You can do that using command-line tools like curl, or if you want to stay within java land, you could try this example on exampledepot. Use your favourite search engine to search for more examples, e.g. with search terms such as "sending GET requests through a url".

In your situation, where you need to send information for username and password, you would need to look at the html and find the url for the form element's action attribute. Then you need to find the names of the username and password fields. Using these names as url parameters, you can construct a GET request that mimics sending a form.

NOTE: usually storing a password in plain text in code and/or sending it in plain text to a website is not a good thing to do.