Java HttpURLConnection发布方法不起作用

Question

I am using HttpURLConnection to send data to a server via POST. I set the headers then get the output stream and write some bytes then close the output stream.

I am trying to get the next page for schedule details from given url. But some how i am not getting the result. Please help anybody if you know any issue in this code.

I am getting first page with error instead of second page. "The station combination you have chosen is invalid. Please call the LIRR Travel Information Center at (718) 217-5477 and ask for a representative for more information."

     public static void main(String[] args) throws Exception {
        String url = "http://lirr42.mta.info";
        String cookie = retrieveCookies(url);
        String urlParameters = "FromStation=56&ToStation=8&RequestDate=08/24/2013&RequestTime=01:00&RequestAMPM=PM&sortBy=1&schedules=schedules";
        String page = postHttpPage(url + "/index.php", urlParameters, cookie);
        System.out.println(page);
        System.out.println();
    }

    public static String postHttpPage(String url, String urlParameters, String cookie) throws Exception {
        System.out.println("\nSending 'POST' request to URL : " + url);
        URL obj = new URL(url);
        HttpURLConnection conn = (HttpURLConnection) obj.openConnection();
        return postPage(conn, urlParameters, cookie);
    }

    private static String postPage(HttpURLConnection conn, String urlParameters, String cookie) throws Exception {
        conn.setRequestMethod("POST");
        conn.setRequestProperty("User-Agent", "User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.57 Safari/537.36");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setRequestProperty("Content-Length", String.valueOf(urlParameters.getBytes().length));
        conn.setRequestProperty("Content-Language", "en-US");
        conn.setRequestProperty("Cookie", cookie);
        //conn.setInstanceFollowRedirects(true);
        // Send post request
        //conn.setDoInput(true);
        conn.setDoOutput(true);
        DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
        wr.writeBytes(urlParameters);
        //System.out.println("wr : " + wr.size());
        wr.flush();
        wr.close();

        StringBuffer response = new StringBuffer();
        int responseCode = conn.getResponseCode();
        System.out.println("Post parameters : " + urlParameters);
        System.out.println("Response Code : " + responseCode);

        BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String inputLine;

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        return response.toString();
    }

    public static String retrieveCookies(String url) throws IOException{  
        URL obj = new URL(url);
        HttpURLConnection conn = (HttpURLConnection) obj.openConnection();
        String cookies=conn.getHeaderField("Set-Cookie");  
        System.out.print("cookies: " + cookies);
        conn.disconnect();
        return cookies; 
    }  

Answer 1

You are missing the "?" Between index.php and the parameters.

Answer 2

You should make

String urlParameters = "FromStation=56&ToStation=8&RequestDate=08/24/2013&RequestTime=01:00&RequestAMPM=PM&sortBy=1&schedules=schedules";

into

String urlParameters = "?FromStation=56&ToStation=8&RequestDate=08/24/2013&RequestTime=01:00&RequestAMPM=PM&sortBy=1&schedules=schedules";

Answer 3

HttpURLConnection.getResponseCode();

this method may help you.
It forces the connection really establish the connection.
may be you want to use Apache HttpClient to make your life easier...