Java Regex: How detect a URL with file extension

Question

How create a REGEX to detect if a "String url" contains a file extension (.pdf,.jpeg,.asp,.cfm...) ?

Valids (without extensions):

• http://www.yahoo.com
• http://dbpedia.org/ontology/
• http://www.rdf.com.br

Invalids (with extensions):

• http://www.thesis.com/paper.pdf
• http://pics.co.uk/mypic.png
• http://jpeg.com/images/cool/the_image.JPEG

Thanks, Celso

Answer 1

In Java, you are better off using String.endsWith() This is faster and easier to read. Example:

"file.jpg".endsWith(".jpg") == true

Answer 2

Alternative version without regexp but using, the URI class:

import java.net.*;

class IsFile { 
  public static void main( String ... args ) throws Exception { 
    URI u = new URI( args[0] );
    for( String ext : new String[] {".png", ".pdf", ".jpg", ".html"  } ) { 
      if( u.getPath().endsWith( ext ) ) { 
        System.out.println("Yeap");
        break;
      }
    }
  }
}

Works with:

java IsFile "http://download.oracle.com/javase/6/docs/api/java/net/URI.html#getPath()"