使用HttpURLConnection的多个Http请求和响应

Question

Good afternoon in my timezone.

I am developing an very simple http bot. I am using the javax.net.ssl.HttpsURLConnection class and i have to make multiple requests. Snippet of code :

HttpURLConnection urlConnection =
    (HttpURLConnection) new URL(url+"?"+firstParameters).openConnection();
urlConnection.setRequestProperty("Accept-Charset", "UTF-8");
headerFields = urlConnection.getHeaderFields();
keys = headerFields.keySet();
for(String key : keys){
    if(key != null && key.contains("ookie")){
        cookies = urlConnection.getHeaderField(key);
        break;
    }
}
for(String cookie : cookies.split(";")){
    if(cookie.contains("JSESSION")){
        JSESSION = cookie.split("=")[1];
        break;
    }
}
document = new InputSource(urlConnection.getInputStream());
parser.setDocument(document);
attributesId.put("name",new ArrayList<String>(Arrays.asList(attributesNames)));
elementsIds.put("INPUT",attributesId);
elements = parser.getValues(elementsIds);
for(String attr : attributesNames){
    secondParameters = secondParameters.replaceAll("#r"+index,elements.get(attr));
}
urlConnection.getInputStream().close();
//Second call 
urlConnection = (HttpURLConnection) new URL(url2).openConnection();
urlConnection.setRequestMethod("POST");
urlConnection.setRequestProperty("Cookie", "JSESSIONID="+JSESSION);
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
payload = new PrintWriter(urlConnection.getOutputStream());
payload.print(secondParameters);
payload.flush();
payload.close();

Summarizing the code above, first i do a request without any payload and i am able to see the correct response from the server, but the problem is when i make the second request (now with payload and with the JSESSION cookie), what i receive it his the same response that i received in the first request, it looks like i am making the first request again. So my question is , what i am doing wrong ? I just need to open one connection, and then change the headers and payload ? There is any tutorial related with multiple http requests(with mixed methods , post and get)?

Thanks in advance

With the best regards

Answer 1

I've never used HttpURLConnection before. I usually use Apache's HTTPClient code . There are a lot of docs and tutorials about it on their home page.

I couldn't find any tutorials about HttpURLConnection but I tried it out. Here's my little program which is similar to yours.

http://pastie.org/2706758

It seems to work:

1. It makes an initial request to get session cookie.
2. It processes the response headers to get the cookie.
3. It makes a second request to authenticate the session with the cookie in the request.
4. If a correct username/password is used then the results show that the session is authenticated.

Couple of things that I noticed about your code:

• You code does not handle multiple Cookie headers on the response. Mine seems to handle that better.
• Are you sure that all you need is JSESSION ? Maybe there are other cookies you are missing?
• Have you debugged your code to make sure that your JSESSION cookie gets set appropriately? I added some trim() calls in my cookie processing code to make sure some spaces didn't slip in there.
• I can't see the real value of your secondParameters . I have no idea if they are valid. Have you debugged your code to verify the secondParamters value looks good. You can see in my code what I'm posting to the server. Btw, I'd use a StringBuilder instead of + to build them.

Hope this helps.