I need to check whether a URL exists or not. I want to write a servlet for this i.e. to check whether a URL exists or not. If the URL entered does not exist, then it should return some message.
For HTTP you should check for the HTTP status code 404 .
php $url = "http://www.qbaki.com"; // Remove all illegal characters from a url $url = filter_var($url, FILTER_SANITIZE_URL); // Validate url if (filter_var($url, FILTER_VALIDATE_URL) !== false) { echo("$url is a valid URL"); } else { echo("$url is not a valid URL"); } ?>
Better solution for HTTP :
public static boolean exists(String URLName){
try {
HttpURLConnection.setFollowRedirects(false);
// note : you may also need
// HttpURLConnection.setInstanceFollowRedirects(false)
HttpURLConnection con =
(HttpURLConnection) new URL(URLName).openConnection();
con.setRequestMethod("HEAD");
return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
}
catch (Exception e) {
e.printStackTrace();
return false;
}
}
If you are looking for any other URL try this code
public static boolean exists(String URLName){
boolean result = false;
try {
url = new URL("ftp://ftp1.freebsd.org/pub/FreeBSD/");
//url = new URL("ftp://ftp1.freebsd.org/pub/FreeBSD123/");//this will fail
input = url.openStream();
System.out.println("SUCCESS");
result = true;
} catch (Exception ex) {
Logger.getLogger(NewClass.class.getName()).log(Level.SEVERE, null, ex);
}
return result;
}
Source :http://www.rgagnon.com/javadetails/java-0059.html
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