remove empty tag pairs from HTML fragment

Question

I have a user-submitted string that contains HTML content such as

"<p></p><div></div><p>Hello<br/>world</p><p></p>"

I would like to transform this string such that empty tag pairs are removed (but empty tags like <br/> are retained). For example, the result of this transformation should convert the string above to

"<p>Hello<br/>world</p>"

I'd like to use JSoup to do this, as I already have this on my classpath, and it would be easiest for me to perform this transformation on the server-side.

Answer 1

Here is an example that does just that (using JSoup):

String html = "<p></p><div></div><p>Hello<br/>world</p><p></p>";
Document doc = Jsoup.parse(html);

for (Element element : doc.select("*")) {
    if (!element.hasText() && element.isBlock()) {
        element.remove();
    }
}

System.out.println(doc.body().html())

The output of the code above is what you are looking for:

<p>Hello<br />world</p>

Answer 2

Not really familiar with jsoup, but you could do this with a simple regex replace:

String html = "<p></p><div></div><p>Hello<br/>world</p><p></p>";
html = html.replaceAll("<([^>]*)></\\1>", "");

Although with a full parser you could probably just drop empty content during processing, depending on what you're eventually going to do with it.