try {
    Connection.Response res1 = Jsoup.connect("http://site.ru")
            .data("login","admin")
            .data("passwd","admin")
            .data("send","Войти")
            .method(Connection.Method.POST)
            .execute();
    Map loginCoockies = res1.cookies();
    System.out.println(loginCoockies);
    Document doc = Jsoup.connect("http://site.ru")
            .cookies(loginCoockies)
            .get();
    System.out.println(doc);
} catch (IOException e) {
    System.out.println(e);
}
return null;