當我們需要抓取需要登入的網站的資訊或者實現模擬登入時，我們需要得到第一次登入網站的cookie,以便於下次登入可以不用post引數實現登入，只要將cookie放入標頭檔案就好，這是之前寫的模擬登入學校教務的程式碼，記錄以便查閱。

public String DoLogin(final String user, final String password, final String verifation) {

                DefaultHttpClient   defaultclient = new DefaultHttpClient();  

                //設定post引數
 

                List<NameValuePair> params = new ArrayList<NameValuePair>();

                params.add(new BasicNameValuePair("groupId", ""));
                params.add(new BasicNameValuePair("j_username", user));
                params.add(new BasicNameValuePair("j_password", password));
                params
 
.add(new BasicNameValuePair("j_captcha", verifation));
                params.add(new BasicNameValuePair("login", "登入"));

                //獲得個人主介面的HTML
                try {
                     HttpPost httpPost = new HttpPost(LOGINURL);
                     System.out.println(LOGINURL);                  
                     httpPost.setHeader("Cookie"
 
, Cookie);                    
                     HttpResponse httpResponse;
                     httpPost.setEntity((HttpEntity) new UrlEncodedFormEntity(params, HTTP.UTF_8));
                     httpResponse = defaultclient.execute(httpPost);
                     httpPost.setHeader("Cookie", Cookie);
                     System.out.println(Cookie);
                     if (httpResponse.getStatusLine().getStatusCode() == 200) {
                          StringBuffer sb = new StringBuffer();
                          HttpEntity entity = httpResponse.getEntity();
                          MAINBODYHTML = EntityUtils.toString(entity);        


                    }

                    if(httpResponse.getStatusLine().getStatusCode() == 302){
                        String locationUrl=httpResponse.getLastHeader("Location").getValue();  
                        System.out.println(locationUrl);
                        LOGINURL=locationUrl;
                        System.out.println("302");
                        DoLogin(user, password, verifation);
                    }                 
                    else{
                        StringBuffer sb = new StringBuffer();
                        HttpEntity entity = httpResponse.getEntity();
                        MAINBODYHTML = EntityUtils.toString(entity);
                       System.out.println( MAINBODYHTML);
                    }
                } catch (UnsupportedEncodingException e) {

                    System.out.println("驗證碼不正確");
                    e.printStackTrace();
                } catch (ClientProtocolException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                LOGINURL="http://jw.djtu.edu.cn/academic/j_acegi_security_check";      

                return MAINBODYHTML; 
    }