Validating URL in Java
java, url, validation
Solution
For the benefit of the community, since this thread is top on Google when searching for "url validator java"
Catching exceptions is expensive, and should be avoided when possible. If you just want to verify your String is a valid URL, you can use the UrlValidator class from the Apache Commons Validator project.
For example:
String[] schemes = {"http","https"}; // DEFAULT schemes = "http", "https", "ftp"
UrlValidator urlValidator = new UrlValidator(schemes);
if (urlValidator.isValid("ftp://foo.bar.com/")) {
System.out.println("URL is valid");
} else {
System.out.println("URL is invalid");
}
Problem
I wanted to know if there is any standard APIs in Java to validate a given URL? I want to check both if the URL string is right i.e. the given protocol is valid and then to check if a connection can be established. I tried using HttpURLConnection, providing the URL and connecting to it. The first part of my requirement seems to be fulfilled but when I try to perform HttpURLConnection.connect(), 'java.net.ConnectException: Connection refused' exception is thrown. Can this be because of proxy settings? I tried setting the System properties for proxy but no success. Let me know what I am doing wrong.