How to check if a URL exists or returns 404 with Java?

Question

String urlString = "http://www.nbc.com/Heroes/novels/downloads/Heroes_novel_001.pdf"; URL url = new URL(urlString); if(/* Url does not return 404 */) {     System.out.println("exists"); } else {     System.out.println("does not exists"); } urlString = "http://www.nbc.com/Heroes/novels/downloads/Heroes_novel_190.pdf"; url = new URL(urlString); if(/* Url does not return 404 */) {     System.out.println("exists"); } else {     System.out.println("does not exists"); } 

This should print

exists does not exists 

TEST

public static String URL = "http://www.nbc.com/Heroes/novels/downloads/";  public static int getResponseCode(String urlString) throws MalformedURLException, IOException {     URL u = new URL(urlString);      HttpURLConnection huc =  (HttpURLConnection)  u.openConnection();      huc.setRequestMethod("GET");      huc.connect();      return huc.getResponseCode(); }  System.out.println(getResponseCode(URL + "Heroes_novel_001.pdf"));  System.out.println(getResponseCode(URL + "Heroes_novel_190.pdf"));    System.out.println(getResponseCode("http://www.example.com"));  System.out.println(getResponseCode("http://www.example.com/junk"));            

Output

200
200
200
404

SOLUTION

Add the next line before .connect() and the output would be 200, 404, 200, 404

huc.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)"); 

Answer 1

You may want to add

HttpURLConnection.setFollowRedirects(false); // note : or //        huc.setInstanceFollowRedirects(false) 

if you don't want to follow redirection (3XX)

Instead of doing a "GET", a "HEAD" is all you need.

huc.setRequestMethod("HEAD"); return (huc.getResponseCode() == HttpURLConnection.HTTP_OK);