seehttp://mindprod.com/jgloss/authenticator.html
You simply write code to provide id/password and Java magically does
the rest.
Thanks Roedy.
What about Cookie? Firefox stores this cookie called "stn"
after I logged in, but if I delete this cookie and refresh,
I will be kicked back to the front login screen. So I think
it is the session id cookie. Don't I need to send back
a session id every time I POST?
Also, how does the Autheticator knows what are the <input>
names for the username and password? Shouldn't they be specified
somehow? (for this site, they are "LoginName" and "Password")
Below is my attempt using the Autheticator, but instead of
next_page being the string of the next page after a successful login,
it returned the front page of the site. So the method is not
successful. Do you have any idea what is wrong?
Many thanks!
Anthony
My Code
========
import java.net.*;
import java.io.*;
public class Test2 {
private String login_url_str = "
https://www.comsec.com.au/
Default.aspx";
public Test2() {
}
public static void main(String[] args) {
Test2 test1 = new Test2();
test1.execute();
}
private void execute() {
//Setup for https
java.security.Security.addProvider(new
com.sun.net.ssl.internal.ssl.
Provider());
System.setProperty("java.protocol.handler.pkgs",
"com.sun.net.ssl.internal.
www.protocol");
Authenticator.setDefault( new MyAuthenticator() );
try {
URL url = new URL(login_url_str);
//For handling POST request
String next_page = getURLPostString(url,"");
System.out.println(next_page);
} catch (IOException ex) {
System.out.println(ex);
System.exit(1);
}
}
/** Post a string to an URL and get the reply as a string. Returns
an empty
string if things didn't work out. */
//code from:
http://martin.nobilitas.com/java/cookies.html
private String getURLPostString(URL url, String body) {
StringBuffer sb = new StringBuffer();
// find the newline character(s) on the current system
String newline = null;
try {
newline = System.getProperty("line.separator");
} catch (Exception e) {
newline = "\n";
}
try {
// URL must use the http protocol!
HttpURLConnection conn = (HttpURLConnection)
url.openConnection();
conn.setRequestMethod("POST");
conn.setAllowUserInteraction(false); // you may not ask
the user
conn.setDoOutput(true); // we want to send things
// the Content-type should be default, but we set it
anyway
conn.setRequestProperty("Content-type",
"application/x-www-form-
urlencoded");
// the content-length should not be necessary, but we're
cautious
conn.setRequestProperty("Content-length",
Integer.toString(body.length()));
// get the output stream to POST our form data
OutputStream rawOutStream = conn.getOutputStream();
PrintWriter pw = new PrintWriter(rawOutStream);
pw.print(body); // here we "send" our body!
pw.flush();
pw.close();
// get the input stream for reading the reply
// IMPORTANT! Your body will not get transmitted if you
get the
// InputStream before completely writing out your output
first!
InputStream rawInStream = conn.getInputStream();
// get response
BufferedReader rdr = new BufferedReader(new
InputStreamReader(
rawInStream));
String line;
while ((line = rdr.readLine()) != null) {
sb.append(line);
sb.append(newline);
}
return sb.toString();
} catch (Exception e) {
System.out.println("Exception " + e.toString());
e.printStackTrace();
}
return ""; // an exception occurred
}
}
class MyAuthenticator extends Authenticator
{
/**
* Called when password authorization is needed.
* @return The PasswordAuthentication collected from the
* user, or null if none is provided.
*/
protected PasswordAuthentication getPasswordAuthentication()
{
return new PasswordAuthentication ( "usernameblah",
"passwordblah".toCharArray() );
}
}
