Regex to select string preceding by specific string

Question

I have big xml in java object. And I want to replace

<countryChannel countryCode="CountryCode"/>

with 

<countryChannel countryCode="CountryCode" active="true"></countryChannel>

Here is samle xml (input)

</articleMedia>
                    <channels>
                        <countryChannel countryCode="CountryCode"/>
                    </channels>

</articleMedia>
                    <channels>
                        <countryChannel countryCode="CountryCode"/>
                    </channels>

                    </articleMedia>
                    <channels>
                        <countryChannel countryCode="CountryCode"/>
                    </channels>

May I know please using regex how can I select only "/>" portion of all strings preceding by countryChannel countryCode="CountryCode" ?

I have one regex which only selects the whole strings https://regex101.com/r/NLHy2Y/1, but how can I select only all "/>" preceding by "countryChannel countryCode="CountryCode"" ?

`I have big xml in java object` ... then don't use regex to parse it, use a parser. — Tim Biegeleisen, Mar 13 '18 at 11:58
https://stackoverflow.com/questions/5059224/which-is-the-best-library-for-xml-parsing-in-java check this also — xMilos, Mar 13 '18 at 11:59
@TimBiegeleisen, but what would be the regex if I needed ..? — Squeez, Mar 13 '18 at 12:04

score 1 · Accepted Answer · answered Mar 13 '18 at 12:16

In this case you don't even need a regex. You can use String.replace() with the right texts:

String input = "<countryChannel countryCode=\"CountryCode\"/>\r\nsalala\r\n<countryChannel countryCode=\"CountryCode\"/>";
String replacement = input.replace("<countryChannel countryCode=\"CountryCode\"/>", "<countryChannel countryCode=\"CountryCode\" active=\"true\"></countryChannel>");
System.out.println(replacement);

Here is a trick: if you want to edit an XML as text, then you must make some assumptions about how the xml is serialized. In this case I made the assumption that:

All you want to edit only those <countryChannel> tags that have one countryCode attribute
And their value is always CountryCode
And all those tags are serialized like this: <countryChannel countryCode="CountryCode"/>

Probably you want to include other country codes too. As long as they don't contain quotes, you can do it with the following regex: "<countryChannel countryCode=\"([^\"]*)\"/>" and use the backreference $1 in the replacement. In this case you need the String.replaceAll() method, because that evaluates regexs. This is how the code looks like:

String input = "<countryChannel countryCode=\"CountryCode123\"/>\r\nsalala\r\n<countryChannel countryCode=\"CountryCode456\"/>";
String replacement = input.replaceAll("<countryChannel countryCode=\"([^\"]*)\"/>", "<countryChannel countryCode=\"$1\" active=\"true\"></countryChannel>");
System.out.println(replacement);

Explanation: [^...] is a negated character class. I.e. everything, except those characters. So [^"]* matches characters, except the quote. Which is cool because we want to stop matching at the end of the actual attribute.

So, you can check your big xml file and make sure that you have the right assumptions.

Disclaimer:

Do not put such regexes into production. These regexes are cool for editing files for yourself, as long as you check them manually. However, for production you better use XSLT.

"And their value is always CountryCode", nope it can be changed ...! Only that part(value) is dynamic — Squeez, Mar 13 '18 at 12:18
Check the second code example then. The one that uses `replaceAll()` — Tamas Rev, Mar 13 '18 at 12:19

Regex to select string preceding by specific string

1 Answers1

Disclaimer: