Passing data to an html POST form using Java

Question

I have an HTML form that looks about like this:

<form name="form1" method="post" action="/confirm.asp">
    <input type="text" name="data1" size="20" value=""><br>
    <input type="text" name="data2" size="20" value=""><br>
    <input type="Submit" name=submit value="Submit">
</form>

I want to use Java to pass data todata1 and data2 and read the page that follows when the form is submitted. Since this is a method=post, I cannot use http://somesite.com/confirm.asp?data1=foo&data2=foo.

Can one please help?

Are you sure you want to do it in Java and not Javascript? — Roddy of the Frozen Peas
– Roddy of the Frozen Peas, Commented Jul 16, 2012 at 2:25
Under the part that says Firing a HTTP POST request with query parameters, it gives you example code and tells you what to do with "data1" and "data2". — Jon Lin
– Jon Lin, Commented Jul 16, 2012 at 2:31

Eng.Fouad · Accepted Answer · 2012-07-16 02:44:44Z

4

/* create a new URL and open a connection */
URL url = new URL("http://somesite.com/confirm.asp");
URLConnection con = url.openConnection();
con.setDoOutput(true);

/* wrapper the output stream of the connection with PrintWiter so that we can write plain text to the stream */
PrintWriter wr = new PrintWriter(con.getOutputStream(), true);

/* set up the parameters into a string and send it via the output stream */
StringBuilder parameters = new StringBuilder();
parameters.append("data1=" + URLEncoder.encode("value1", "UTF-8"));
parameters.append("&");
parameters.append("data2=" + URLEncoder.encode("value2", "UTF-8"));
wr.println(parameters);
wr.close();

/* wrapper the input stream of the connection with BufferedReader to read plain text, and print the response to the console */
BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream()));
String line;
while((line = br.readLine()) != null) System.out.println(line);
br.close();

edited Jul 16, 2012 at 2:44

answered Jul 16, 2012 at 2:34

Eng.Fouad

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9 Comments

Christina Stewart Over a year ago

I'm a Java novice. Can you explain the code? What do I have to change? value1 and value2 to the data I want to pass? And then is line the html source of the page after the form is submitted?

Jon Lin Over a year ago

Wouldn't parameters be "data1=value1data2=value2"?

Eng.Fouad Over a year ago

I used URLEncoder in case of using spaces or special characters like +.

Jon Lin Over a year ago

No, I mean there's nothing separating the 2 pairs, (no "&")

Christina Stewart Over a year ago

Eng.Fouad, sir, can you please respond to my questions? I think this is kind of what I'm looking for!

|

hqt · Accepted Answer · 2012-07-16 03:26:59Z

Here is the code from Link. Hope this helps you :)

import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpPostForm
{
  public static void main(String[] args)
  {
    try
    {
      URL url = new URL( "http://www.aaaa.com/xyz.asp" );

      HttpURLConnection hConnection = (HttpURLConnection)
                             url.openConnection();
      HttpURLConnection.setFollowRedirects( true );

      hConnection.setDoOutput( true );
      hConnection.setRequestMethod("POST"); 

      PrintStream ps = new PrintStream( hConnection.getOutputStream() );
      ps.print("param1=abcd&amp;param2=10341");
      ps.close();

      hConnection.connect();

      if( HttpURLConnection.HTTP_OK == hConnection.getResponseCode() )
      {
        InputStream is = hConnection.getInputStream();
        OutputStream os = new FileOutputStream("output.html");
        int data;
        while((data=is.read()) != -1)
        {
          os.write(data);
        }
        is.close();
        os.close();
        hConnection.disconnect();
      }
    }
    catch(Exception ex)
    {
      ex.printStackTrace();
    }
  }
}

FThompson · Accepted Answer · 2012-07-16 03:44:05Z

2

To write a POST request in Java, you should connect to your target URL via a URLConnection, where you then write the bytes of head boundary, the boundary message (where the keys, values, and any other request data is placed), and the end boundary.

I wrote a PostProcess class for an application of mine, which allows for asynchronous POST request uploading, key-value parameters, file parameters (i.e. the file upload input in a form), and upload progress tracking. It also records the server response.

For the sake of size and readability, I have uploaded the code externally to http://textu.be/T

answered Jul 16, 2012 at 3:44

FThompson

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Comments

theMind · Accepted Answer · 2015-11-09 14:53:21Z

1

Try following codes

String url="www.somesite.com";     
Document doc = Jsoup.connect(url).data("data1", "foo").data("data2","foo")
                .userAgent("Mozilla/5.0 (Windows; U; WindowsNT 5.1; en-US; rv1.8.1.6) Gecko/20070725 Firefox/2.0.0.6")
                .referrer("http://www.google.com").post();

answered Nov 9, 2015 at 14:53

theMind

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