FormAuthenticator.java

import java.io.IOException;
import java.util.ArrayList;
import java.util.Map;

import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.ClientRequestContext;
import javax.ws.rs.client.ClientRequestFilter;
import javax.ws.rs.client.Entity;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.Form;
import javax.ws.rs.core.NewCookie;
import javax.ws.rs.core.Response;

/**
 * License : Apache License 2.0
 * 
 * The idea comes from : http://www.adam-bien.com/roller/abien/entry/client_side_http_basic_access
 * 
 * @author Michael Bornholdt Nielsen mni@jarry.dk
 * 
 */
public class FormAuthenticator implements ClientRequestFilter {

	private ArrayList<Object> cookies;

	public FormAuthenticator(String baseUri, String username, String password) {

		cookies = new ArrayList<>();

		Client client = ClientBuilder.newClient();

		WebTarget baseTarget = client.target(baseUri);

		Form form = new Form();
		form.param("j_username", username);
		form.param("j_password", password);
		Response response = baseTarget.path("j_security_check")
				.request("application/x-www-form-urlencoded")
				.post(Entity.form(form));

		Map<String, NewCookie> cr = response.getCookies();

		for (NewCookie cookie : cr.values()) {
			cookies.add(cookie.toCookie());
		}
	}

	public void filter(ClientRequestContext requestContext) throws IOException {
		if (cookies != null) {
			requestContext.getHeaders().put("Cookie", cookies);
		}
	}
}