Java httpclient登录网站下载文件-会话问题!

I log on to a website using the POST method (httpclient from apache). I let the HttpClient execute the HttpPost, let the connection manager release it and then I want to post a GET message that opens a php-URL file to download a pdf. But all I get is the html file of a "session expired" page (println: I log on to a website using the POST method (ht