What would be the correct regular expression for extracting a href from a html line? (Java)

Question

Hi I am trying to extract text which a href defines in a html line. For example:

<link rel="stylesheet" href="style.css" type="text/css">

I want to get "style.css" or:

<a href="target0.html"><img align="center" src="thumbnails/image001.jpg" width="154" height="99">

I want to get "target0.html"

What would be the correct Java code to do this?

I think the answer on this question is what you are looking for: http://stackoverflow.com/questions/1670593/java-i-have-a-big-string-of-html-and-need-to-extract-the-href-text — DiogoDoreto, Nov 21 '11 at 18:29
Mandatory SO link: http://stackoverflow.com/questions/1732348 Read the answer with the most upvotes ; ) — TacticalCoder, Nov 21 '11 at 19:06

score 1 · Accepted Answer · answered Nov 21 '11 at 18:36

    public static String getHref(String str)
    {
        int startIndex = str.indexOf("href=");
        if (startIndex < 0)
            return "";
        return str.substring(startIndex + 6, str.indexOf("\"", startIndex + 6));
    }

This method assumes that the html is well formed and it only works for the first href in the string but I'm sure you can extrapolate from here.

score 1 · Answer 2 · answered Nov 21 '11 at 18:45

I realize you asked about using regular expressions, but jsoup makes this so simple and is much less error prone:

import java.io.IOException;

import nu.xom.ParsingException;
import nu.xom.ValidityException;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import org.xml.sax.SAXException;

public class HrefExtractor {
    public static void main(final String[] args) throws SAXException, ValidityException, ParsingException, IOException {
        final Document document = Jsoup.parse("<a href=\"target0.html\"><img align=\"center\" src=\"thumbnails/image001.jpg\" width=\"154\" height=\"99\">");
        final Elements links = document.select("a[href]");
        for (final Element element : links) {
            System.out.println(element.attr("href"));
        }
    }
}

score 0 · Answer 3 · edited Jun 25 '21 at 07:08

0

I have not try the following but it should be something like this:

'Pattern.compile("<(?:link|a\s+)[^>]*href=\"(.*?)\"")'

But I'd recommend you to use one of available HTML or even XML parsers for this task.

edited Jun 25 '21 at 07:08

Nimantha

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answered Nov 21 '11 at 18:32

AlexR

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What would be the correct regular expression for extracting a href from a html line? (Java)

3 Answers3