I have a problem with the replaceAll for a multiline string:
String regex = "\\s*/\\*.*\\*/";
String testWorks = " /** this should be replaced **/ just text";
String testIllegal = " /** this should be replaced \n **/ just text";
testWorks.replaceAll(regex, "x");
testIllegal.replaceAll(regex, "x");
The above works for testWorks, but not for testIllegal!? Why is that and how can I overcome this? I need to replace something like a comment /* ... */ that spans multiple lines.
You need to use the Pattern.DOTALL flag to say that the dot should match newlines. e.g.
Pattern.compile(regex, Pattern.DOTALL).matcher(testIllegal).replaceAll("x")
or alternatively specify the flag in the pattern using (?s) e.g.
String regex = "(?s)\\s*/\\*.*\\*/";
Add Pattern.DOTALL to the compile, or (?s) to the pattern.
This would work
String regex = "(?s)\\s*/\\*.*\\*/";
The meta character . matches any character other than newline. That is why your regex does not work for multi line case.
To fix this replace . with [\d\D] that matches any character including newline.
[\d\D] for . (which normally means [^\n], at least in Pattern.UNIX_LINES mode) strikes me as inappropriate because it is not obvious what it is doing, because it is 6 chars for 1, and because there are other ways of doing this.
"String s = \"/*\"; /* comment */"