How can I programmatically test an HTTP connection?

Question

Using Java, how can I test that a URL is contactable, and returns a valid response?

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Answer 1

import org.apache.commons.validator.UrlValidator;

public class ValidateUrlExample {

    public static void main(String[] args) {

        UrlValidator urlValidator = new UrlValidator();

        //valid URL
        if (urlValidator.isValid("http://www.mkyong.com")) {
            System.out.println("url is valid");
        } else {
            System.out.println("url is invalid");
        }

        //invalid URL
        if (urlValidator.isValid("http://invalidURL^$&%$&^")) {
            System.out.println("url is valid");
        } else {
            System.out.println("url is invalid");
        }
    }
}

Output:

url is valid
url is invalid

source : http://www.mkyong.com/java/how-to-validate-url-in-java/