POST Request Java

[Abebe Kebede]

Hi every one.

I really stack on this issue. I am making a code that makes POST Request to a server with username and password as a parameter. I dont know why i am getiing 500 error. Here is the code, Please check it for me.

This is what i did.
1. First i send GET request and read the header of the HTTP response to
get the CookieName and CookieValue. This is working.

2. Then i create another HTTP connection to do the post Request, But
this time since it is a new connection the server generates NEW and
different Cookie(To be exact NEW session_ID)from the first one. So I am
sending NEW Request with the OLD session_ID. And i have to create a NEW
connection for ever Request i made, so i cant do both the GET and post
Requests with one Connection.

This one is my potential problem.

1. Do you think i can do the POST request without the Cookie sent again, based on the server login detail below?
2. If not, how can i do the POST request with the connection i created to read theheader(two requests with just one HTTP connection)?
3. The result i am getting is 500 error, Do you think the problem is ONLY from ther server side?
4. Finally What does it mean if i get "Wrong Username and password " message, does that mean surely my post request does work ?
Thank you!

import java.net.*;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URLEncoder;
class Test {
	
	public static final HttpURLConnection openConnection(URL url, boolean in, boolean out,String requestMethode) throws IOException{
        HttpURLConnection con = (HttpURLConnection) url.openConnection ();
        con.setDoInput(in);
        con.setDoOutput (out);
        if(requestMethode == null){
            requestMethode = "GET";
        }
        con.setRequestMethod(requestMethode);
        con.setRequestProperty ("Content-Type", "application/x-www-form-urlencoded");
        return con;
    }
	
	public static final String getCookies(HttpURLConnection con){ // method for getting the cookies
		try {
			con.connect();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		String headerName=null; String cookie=null; 
		for (int i=1; (headerName = con.getHeaderFieldKey(i))!=null; i++) {
		 	if (headerName.equals("Set-Cookie"))               
			 cookie = con.getHeaderField(i); 		 	
		}
		cookie = cookie.substring(0, cookie.indexOf(";"));
        String cookieName = cookie.substring(0, cookie.indexOf("="));
        String cookieValue = cookie.substring(cookie.indexOf("=") + 1, cookie.length());
        System.out.println(cookieName);
        System.out.println(cookieValue);
        
        return cookieName+"="+cookieValue;
    }
	public static void POST_Req(HttpURLConnection conn, String cookieHeader)
	{
		try {
				// Encoding Login Data
			
				String data=URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode("Ulm.Mule", "UTF-8") +
				"&" + URLEncoder.encode("password", "UTF-8") + URLEncoder.encode("123456", "UTF-8");
				
				// Posting the login data to the server
								
				conn.setRequestProperty("cookie", cookieHeader);				
				OutputStreamWriter writer=new OutputStreamWriter(conn.getOutputStream());
				writer.write(data);
				writer.flush();		
				
			    //Reading response of the server				
				
				BufferedReader reader=new BufferedReader(new InputStreamReader(conn.getInputStream()));
				String response;
				while ((response=reader.readLine())!=null) {
					System.out.println(response);
				}
				writer.close();
				reader.close();
			} catch (IOException e) {
				
				e.printStackTrace();
			}
			
	}
	
	public static void main(String[] args) throws IOException
	{
		// connection for getting the cookies
		URL con=new URL("http://address/do_login");
		HttpURLConnection test=openConnection(con, true, true, "GET");
		String cookie= getCookies(test);
		System.out.println(cookie);
		//Another connection for POST Request
		URL con2=new URL("http://address/do_login");
		HttpURLConnection test2=openConnection(con2, true, true, "POST");
	    POST_Req(test2, getCookies(test2));
	}
	
	
}

Here is the Login deatail of the server, python based

import urllib, urllib2 
import cookielib 
url = 'http://site address here/do_login' 
values = {'username' : 'your username', 
'password' : 'your password'} 
try: 
data = urllib.urlencode(values) 
req = urllib2.Request(url, data) 
cj = cookielib.CookieJar() 
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj)) 
response = opener.open(req) 
the_page = response.read() 
except Exception, detail: 
print "Err ", detail 

And here is the source of the login page.

<body> 
		<form method=post action=do_login id=mainform> 
			<center> 
			<table> 
				<tr> 
				  <td></td> 
				  <td></td> 
				</tr> 
				<tr> 
					<td><label for="username">Username</label></td> 
					<td><input type=text class='TextField' name=username value=''></td> 
				</tr> 
				<tr> 
					<td><label for="password">Password</label></td> 
					<td><input type=password class=TextField name=password></td> 
				</tr> 
				<tr> 
					<td></td> 
					<td><input type=submit value=Login>  <a href="register">New user</a></td> 
				</tr> 
			</table> 
			</center> 
		</form> 
	</body>