How to use different cookies for each connection using HttpURLConnection and the CookieManager in Java

Question

I needed to connect to a website from multiple threads simultaneously using HttpURLConnection, but use different cookies for each connection. Since Java only supports setting a global CookieManager, I've implemented the following hack.

Instead of calling CookieHandler.setDefault(new CookieManager()), I've implemented a custom CookieHandler which uses a different CookieStore instance for every thread, which is cleared after each request.

I've created class called SessionCookieManager based on the source code of CookieManager.

The cookieJar member variable was removed, and its usage has been replaced by getCookieStore().

The following code was added:

public class SessionCookieManager extends CookieHandler {
    private final static SessionCookieManager ms_instance = new SessionCookieManager();

    public static SessionCookieManager getInstance() {
        return ms_instance;
    }

    private final static ThreadLocal<CookieStore> ms_cookieJars = new ThreadLocal<CookieStore>() {
        @Override
        protected synchronized CookieStore initialValue() { return new sun.net.www.protocol.http.InMemoryCookieStore(); }
    };

    public void clear() {
        getCookieStore().removeAll();
    }

    public CookieStore getCookieStore() {
        return ms_cookieJars.get();
    }

Before the first request, the custom CookieManager is set as the global default CookieHandler:

CookieHandler.setDefault(SessionCookieManager.getInstance());

After every request, the current thread's CookieStore is cleared:

try {
    ...
} finally {
    SessionCookieManager.getInstance().clear();
}

Answer 1

One work around would be to use Cookie header directly instead sending the cookie. See cookie header here: https://msdn.microsoft.com/en-us/library/windows/desktop/aa384321(v=vs.85).aspx which you can change every call.

Cookie: <name>=<value> [;<name>=<value>]...