Question

I am banging my head against this regular expression the whole day.

The task looks simple, I have a number of XML tag names and I must replace (mask) their content.

For example

<Exony_Credit_Card_ID>242394798</Exony_Credit_Card_ID>

Must become

<Exony_Credit_Card_ID>filtered</Exony_Credit_Card_ID>

There are multiple such tags with different names

How do I match any text inside but without matching the tag itself?

EDIT: I should clarify again. Grouping and then using the group to avoid replacing the text inside does not work in my case, because when I add the other tags to the expression, the group number is different for the subsequent matches. For example:

"(<Exony_Credit_Card_ID>).+(</Exony_Credit_Card_ID>)|(<Billing_Postcode>).+(</Billing_Postcode>)"

replaceAll with the string "$1filtered$2" does not work because when the regex matches Billing_Postcode its groups are 3 and 4 instead of 1 and 2

Answer 1

String resultString = subjectString.replaceAll(
    "(?x)    # (multiline regex): Match...\n" +
    "<(Exony_Credit_Card_ID|Billing_Postcode)> # one of these opening tags\n" +
    "[^<>]*  # Match whatever is contained within\n" +
    "</\\1>  # Match corresponding closing tag",
    "<$1>filtered</$1>");