Question

I want to login my gmail and get the contact list automatically with httpClient,
I’ve tryed the method described in the page below:
Android: How to login into webpage programmatically, using HttpsURLConnection
but once it ran to:
String cookie = response.getFirstHeader("Set-Cookie").getValue();
a java.lang.NullPointerException was catched.
I thought it was because the page was moved temporarily, then I coded my code like this:

    private static String uriLogin = "https://mail.google.com";
private static String uriContacts = "https://mail.google.com/mail/shva=1#contacts";

// the account was registered just for test:
private static String myAcc = "httpclient.test";
private static String myPwd = "testpassword";


public static void main(String[] args) throws ClientProtocolException,
        IOException, InterruptedException {
    DefaultHttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost(uriLogin);

    List<NameValuePair> params = new ArrayList<NameValuePair>(3);
    params.add(new BasicNameValuePair("Email", myAcc));
    params.add(new BasicNameValuePair("Passwd", myPwd));
    params.add(new BasicNameValuePair("signIn", "Sign in"));
    post.setEntity(new UrlEncodedFormEntity(params));
    redp("url is:: ", post.getEntity());
    HttpResponse rsp = client.execute(post);

    if (rsp.getStatusLine().getStatusCode() >= 400) {// returns 302 if
                                                        // success
        System.err.println("failed to get the web page!!!");
        System.err.println("status: " + rsp.getStatusLine());
        System.exit(-1);
    }
    redp("status is:: ", rsp.getStatusLine());
    redp("heads of rsp :: ", "");
    pHeads(rsp);
    redp("content is:: ", EntityUtils.toString(rsp.getEntity()));

    String redirect = rsp.getLastHeader("Location").getValue();
    HttpGet get = new HttpGet(redirect);
    rsp = client.execute(get);

    String cookie = rsp.getFirstHeader("Set-Cookie").getValue();
    redp("cookie is:: ", cookie);

    HttpGet getContacts = new HttpGet(uriContacts);
    getContacts.setHeader("Cookie", cookie);
    redp("heads of get [contacts]:: ", "");
    pHeads(getContacts);
    client.getConnectionManager().shutdown();
    client = new DefaultHttpClient(); // without these 2 lines,
                                        // "java.lang.IllegalStateException"
                                        // will be catched
    rsp = client.execute(getContacts);
    redp("heads of rsp (new) ::", "");
    pHeads(rsp);

    InputStream istream = rsp.getEntity().getContent();
    BufferedReader reader = new BufferedReader(new InputStreamReader(
            istream));

    String line;
    p("联系人列表： ");
    while ((line = reader.readLine()) != null) {
        p(line);
    }
    reader.close();
    istream.close();

}// main

public static void pHeads(HttpMessage msg) {
    Header[] headers = msg.getAllHeaders();
    for (int i = 0; i < headers.length; i++)
        p(headers[i].getName() + ": " + headers[i].getValue());

}

public static void p(Object o) {
    System.out.println(o);
}

public static void redp(String head, Object o) throws InterruptedException {
    System.err.println(head);
    if (o.equals("") || o.equals(null))
        return;
    Thread.sleep(100);
    System.out.println(o);
}

}
`
but it still doesn’t work… Any help would be great~~
[BTW, I saw a some people says on the Internet that httpClient was not very acceptable for this kind of job, could you tell me in what kind of project HttpClient is most used?]

Answer 1

From what I’ve seen, You receive the nullPointerEception when you get to response.getLastHeader(“Location”).getValue();
it looks like there is no “Location” tag in the GMail html header. When Java fails to find this, it just throws “I can’t find it”

What you want is the redirect after the POST occurs.
At a quick glance, its something like:
https://accounts.google.com/ServiceLogin?service=mail&passive=true&rm=false&continue=http://mail.google.com/mail/&scc=1&ltmpl=default&ltmplcache=2
but you should double check this.
Hope this helps.