POSTing hidden params from a servlet

[Eric Carlson]

Hi, I'm trying to code an ecommerce site with all the validation done in my servlet. The example they give is just to use a static web page, which is no good for me. So I'm basically trying to duplicate in a servlet what the static one does. Theres nothing special about the static one:

<FORM METHOD="POST" ACTION="https://secure.example.com/authorize/process.cgi" onsubmit="return validator(this)">

<INPUT TYPE=hidden NAME="merchant" VALUE="$merchant">
<INPUT TYPE=hidden NAME="amount" VALUE="$amount">
<INPUT TYPE=hidden NAME="orderref" VALUE="$orderref">
..
</FORM>

My form calls my the validation servlet to populate the vars, then I'm trying to pass them all onto the merchant site exactly as if the user clicked the submit button in the above form. I can't use res.sendRedirect("https://secure.example.com/authorize/process.cgi") or all the params get lost. If I try grabbing the url, adding all the params and doing a POST manually, it does work but the browser never leaves my site, in other words the POST returns the output from the merchant site as a webpage stream, which means the users browser sees the content of the page with the url of my site, not the merchants. Hope I've explained this right, thanks. Heres that POST code, which works but isn't a redirect:

public static String POST(String targetURL, Hashtable contentHash) throws Exception
 
        URL url;
        URLConnection conn;
 
        // The data streams used to read from and write to the URL connection.
        DataOutputStream out;
        BufferedReader in;
 
        // String returned as the result of the POST.
        String returnString = "";
 
        // Create the URL object and make a connection to it.
        url = new URL (targetURL);
        conn = url.openConnection();
 
        // Set connection parameters. We need to perform input and output,
        // so set both as true.
        conn.setDoInput (true);
        conn.setDoOutput (true);
 
        // Disable use of caches.
        conn.setUseCaches (false);
 
        // Set the content type we are POSTing. We impersonate it as
        // encoded form data
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
 
        // get the output stream to POST to.
        out = new DataOutputStream (conn.getOutputStream ());
        String content = "";
 
        // Create a single String value to be POSTED from the parameters passed
        // to us. This is done by making "name"="value" pairs for all the keys
        // in the Hashtable passed to us.
        Enumeration e = contentHash.keys();
        boolean first = true;
        while(e.hasMoreElements())
        {
            // For each key and value pair in the hashtable
            Object key = e.nextElement();
            Object value = contentHash.get(key);
 
            // If this is not the first key-value pair in the hashtable,
            // concantenate an "&" sign to the constructed String
            if(!first)
                content += "&";
 
            // append to a single string. Encode the value portion
            content += (String)key + "=" + URLEncoder.encode((String)value, "UTF-8");
 
            first = false;
        }
 
        // Write out the bytes of the content string to the stream.
        out.writeBytes (content);
        out.flush ();
        out.close ();
 
        // Read input from the input stream.
//        in = new DataInputStream (conn.getInputStream ());
 
        in = new BufferedReader(new InputStreamReader(conn.getInputStream ()));
 
        String str;
        while (null != ((str = in.readLine())))
        {
            returnString += str + "\n";
        }
 
        in.close ();
 
        // return the string that was read.
        return returnString;
    }
}

[Edit by Dave to add code tags]
[ March 19, 2006: Message edited by: David O'Meara ]

[Ulf Dittmer]

Hello "Erik The Viking"-
Welcome to JavaRanch.

On your way in you may have missed that we have a policy on screen names here at JavaRanch. Basically, it must consist of a first name, a space, and a last name, and not be obviously fictitious. Since yours does not conform with it, please take a moment to change it, which you can do right here.

Enjoy your time here.

[Eric Carlson]

Whoops! Sorry, Ok hope the names ok now.
[ March 19, 2006: Message edited by: Eric Carlson ]

[Manesh Kumar]

Originally posted by Erik The Viking:
[QB]Hi, I'm trying to code an ecommerce site with all the validation done in my servlet. The example they give is just to use a static web page, which is no good for me. So I'm basically trying to duplicate in a servlet what the static one does. Theres nothing special about the static one:

<FORM METHOD="POST" ACTION="https://secure.example.com/authorize/process.cgi" onsubmit="return validator(this)">

<INPUT TYPE=hidden NAME="merchant" VALUE="$merchant">
<INPUT TYPE=hidden NAME="amount" VALUE="$amount">
<INPUT TYPE=hidden NAME="orderref" VALUE="$orderref">
..
</FORM>

You need to use response.sendRedirect("http://merchantURL?<construct parameters here");

You need to programatically form the query string and then send redirect to
the client.

This will redirect to the merchat site.

    
response.sendRedirect("https://secure.example.com/authorize/process.cgi?amount="+ request.getParameter("amount") + "&orderref="+ request.getParameter("orderref"));