Question

I have the following code

private String anchorRegex = "\\<\\s*?a\\s+.*?href\\s*?=\\s*?([^\\s]*?).*?\\>";
private Pattern anchorPattern = Pattern.compile(anchorRegex, Pattern.CASE_INSENSITIVE);
String content = getContentAsString();
Matcher matcher = anchorPattern.matcher(content);

while(matcher.find()) {
    System.out.println(matcher.group(1));
}

The call to getContentAsString() returns the HTML content from a web page. The problem I’m having is that the only thing that gets printed in my System.out is a space. Can anyone see what’s wrong with my regex?

Regex drives me crazy sometimes.

Answer 1

You need to delimit your capturing group from the following .*?. There’s probably double quotes " around the href, so use those:

<\s*a\s+.*?href\s*=\s*"(\S*?)".*?>

Your regex contains:

([^\s]*?).*?

The ([^\s]*?) says to reluctantly find all non-whitespace characters and save them in a group. But the reluctant *? depends on the next part, which is .; any character. So the matching of the href aborts at the first possible chance and it is the .*? which matches the rest of the URL.