Question

I have a simple xml file and I want to remove everything before the first <item> tag.

<sometag>
  <something>
   .....
  </something>
  <item>item1
  </item>
  ....
</sometag>

The following java code is not working:

String cleanxml = rawxml.replace("^[\\s\\S]+<item>", "");

What is the correct way to do this? And how do I address the non-greedy issue? Sorry I’m a C# programmer.

Answer 1

Well, if you want to use regex, then you can use replaceAll. This solution uses a reluctant quantifier and a backreference:

String cleanxml = rawxml.replaceAll(".*?(<item>.*)", "$1");

Alternately you can use replaceFirst. This solution uses a positive lookahead.

String cleanxml = rawxml.replaceFirst(".*?(?=<item>)", "");

It makes more sense to just use indexOf and substring, though.

String cleanxml = rawxml.substring(rawxml.indexOf("<item>"));

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The reason why replace doesn’t work is that neither char nor CharSequence overloads is regex-based. It’s simple character (sequence) replacement.

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Also, as others are warning you, unless you’re doing processing of simple XMLs, you shouldn’t use regex. You should use an actual XML parser instead.