testing url connection java html

Question

When I am testing the list of url's to see if the connection is "alive" or "dead", I run into this site: (www.abbapregnancy.org) then site is blank with no information. How can I make an if statement to test for sites like this? Feel free to comment or suggest ideas. My code is currently like this:

try
                    {// Test URL Connection
                    URL url = new URL("http://www."+line);
                    URLConnection conn = url.openConnection();
                    conn.setDoOutput(true);
                    wr = new OutputStreamWriter(conn.getOutputStream());
                    wr.flush();

                    rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));

                    while( !rd.ready() ) {}

                    if( rd.ready())
                    {   
                        //write to output file
                        System.out.println("Good URL: " + line);
                        urlAlive ++;
                        //increment alive line to Alive url file
                        aliveUrl += (line + System.getProperty("line.separator"));                                                          
                    }
                    else // increment dead url 
                        urlDead++;
                    }
                    catch (Exception e) 
                    // increment dead url 
                        {
                            urlDead++;
                        }

From your code it appears you are trying to connect to 'h ttp://www.www.abbapregnancy.org'. Try removing the 'www.' from the start of the site address. — TheSuccessor
– TheSuccessor, Commented Nov 27, 2013 at 17:59
actually its just (abbapregnancy.org) from the list. I self consciously added (www) to the description above — Next_Line_Nick
– Next_Line_Nick, Commented Nov 27, 2013 at 18:14

janos · Accepted Answer · 2013-11-28 08:08:09Z

So you want to check more than just "alive" or "dead". If alive, you also want to know if the content is empty, right?

Since you seem to want to check websites, using http connections makes sense here. For the alive/dead condition, connection attempts will throw an exception if dead. If alive, you can use the status code to check if the request was really successful. Finally, you can use the content-length header to check if the site is up but actually returning empty content. For example like this:

public void checkURL(URL url) throws IOException {
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setRequestMethod("GET");
    System.out.println(String.format("Fetching %s ...", url));
    try {
        int responseCode = conn.getResponseCode();
        if (responseCode == 200) {
            System.out.println(String.format("Site is up, content length = %s", conn.getHeaderField("content-length")));
        } else {
            System.out.println(String.format("Site is up, but returns non-ok status = %d", responseCode));
        }
    } catch (java.net.UnknownHostException e) {
        System.out.println("Site is down");
    }
}

Yasel · Accepted Answer · 2016-05-02 14:38:35Z

public static boolean IsReachable(Context context, String check_url) {
    // First, check we have any sort of connectivity
    final ConnectivityManager connMgr = (ConnectivityManager)   context.getSystemService(Context.CONNECTIVITY_SERVICE);
    final NetworkInfo netInfo = connMgr.getActiveNetworkInfo();
    boolean isReachable = false;

    if (netInfo != null && netInfo.isConnected()) {
        // Some sort of connection is open, check if server is reachable
        try {

            URL url = new URL(check_url);

            // URL url = new URL("http://192.168.100.93/office_com/www/api.php/office_com/Logins/SignUp?api_user=endpoint");
            //URL url = new URL("http://10.0.2.2");
            HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
            urlc.setRequestProperty("User-Agent", "Android Application");
            urlc.setRequestProperty("Connection", "close");
            urlc.setConnectTimeout(10 * 1000);
            try {
                urlc.connect();
                System.out.println("-----fffff");
            } catch (Exception e) {

                System.out.println("-----fffff  " + e);

            }
            isReachable = (urlc.getResponseCode() == 200);
        } catch (IOException e) {

        }
    }

    return isReachable;
}

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