Question

I have one problem when i am using following code snippet

 String regexString=regexPair.get(paramName);

 Pattern p = Pattern.compile(regexString);
 Matcher m = p.matcher(paramMap.get(paramName)[0]);
 status = m.matches();

it return false

where regexPair is hashmap and regexPair.get(paramName) is

"^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$"

while I will ureplace

String regexString="^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$"

then it works fine

paramMap.get(paramName)[0] return [e-mail].

I am not getting why this is occurring please help me.

Answer 1

How do you know that regexPair.get(paramName) is the string you’ve given? Is that the result of some println call?

I suspect the quoting is not entirely the same. It may be that regexPair.get(paramName) actually contains '\\' followed by another '\\' (that is, two real backslashes in succession), while the replacement only contains "\\" (which is a single backslash). Note that the string "(\\." is really only 3 characters long.