How to validate the URL using regex in Java?

Question

I need to check if an URL is valid or not. The URL should contain some subdirectories like as:

example.com/test/test1/example/a.html

The URL should contain subdirectories test, test1 and example. How can I check if the URL is valid using regex in Java?

Answer 1

You can simply pass your URL as an argument to the java.net.URL(String) constructor and check if the constructor throws java.net.MalformedURLException.

EDIT If, however, you simply want to check if a given string contains a given substring, use the String.contains(CharSequence) method. For example:

String url = "example.com/test/test1/example/a.html";
if (url.contains("/test/test1/")) {
    // ...
}

Answer 2

String url = "example.com/test/test1/example/a.html";
List<String> parts = Arrays.asList(url.split("/"));
return (parts.contains("test") && parts.contains("test1") && parts.contains("example"));

Answer 3

Since you want to do in regex, how about this...

Pattern p = Pattern.compile("example\\.com/test/test1/example/[\\w\\W]*");

System.out.println("OK: " + p.matcher("example.com/test/test1/example/a.html").find());
System.out.println("KO: " + p.matcher("example.com/test/test2/example/a.html").find());

Answer 4

This question is answered here using regular expressions: http://stackoverflow.com/questions/163360/regular-expresion-to-match-urls-java

But you can use the library Apache Commons Validators to use some tested validators instead to write your own.

Here is the library: http://commons.apache.org/validator/

And here the javadoc of the URL Validator. http://commons.apache.org/validator/apidocs/org/apache/commons/validator/UrlValidator.html