/**     * 从页面中提取特定input的的Value     * @param formparams     * @param document     * @param elementId     */    private void addFormHiddenElementValue(List<BasicNameValuePair> formparams,            Document document, String elementId) {        Element element = document.getElementById(elementId);        if(element != null){            String elementValue = element.attr("value");            formparams.add(new BasicNameValuePair(elementId,elementValue));        }    }

    /**     * 取得对应URL的Document实例     * @param url     * @return     */    private static Document getDocument(String url) {        Document document = null;        try {            document = Jsoup.connect(url).get();        } catch (IOException e) {            e.printStackTrace();        }        return document;    }

        Document document = getDocument(url);        if(document != null){            List<String> elementIds = new ArrayList<String>();            elementIds.add("__VIEWSTATE");            elementIds.add("__VIEWSTATEGENERATOR");            elementIds.add("__EVENTVALIDATION");            for(String elementId : elementIds){                addFormHiddenElementValue(formparams, document, elementId);            }        }