How to replace "\n" but not ">\n" in a string

Question

Using Java how is it possible replace all "\n" but not ">\n" with "<br/>"?

I need it because I want add a "<br/>" if I have a new line on plain text, but not if I have HTML.

Answer 1

Use a negative lookbehind.

String str = "\n>\n\n";

str = str.replaceAll("(?<!>)\n", "<br />");

This will match the \n, and then backtrack a character to ensure the preceding character wasn't a >.