CODEWITHSUNDEEP
javaregex
gmustudent
gmustudent

Reputation: 2209

Java Regex Escape

I've got this bit of code to grab a url within a textarea. It has been working great until I tried a url with a '+' in it.

Pattern pattern = Pattern.compile("(.*)(https?[://.0-9-?a-z=_#!A-Z]*)(.*)");
Matcher matcher = pattern.matcher(text);

So I tried puting \\+ and \\\\+ in my code but it did not work. So i did some googling and stack overflow problems kept mentioning this guy

Pattern.quote("+");

However, I am not sure how I implement that statement into what I currently have now. If that is even the way I want to go. But I'm assuming I need to do something like this... 

String quote = Pattern.quote("+");
Pattern pattern = Pattern.compile("(.*)(https?[://.0-9-?a-z=_#!A-Z]*)(.*)");
Matcher matcher = pattern.matcher(text);

And then add the variable quote somewhere in the pattern? Please help! I just learned this stuff today I'm brand new to it! Thank you?

Upvotes: 2

Views: 1128

Answers (2)

Jeff Bowman
Jeff Bowman

Reputation: 95784

(https?[://.0-9-?a-z=_#!A-Z]*)

Bear in mind that [ and ] denote a class of characters, and that this means that any character within it will be included. [aegl]+ will match "age", "a", "e", g", "eagle", and "gaggle". It also means that a character listed twice (like /) is completely redundant.

Pattern.quote is useful, but will only return the same string with a backslash preceding any special character. Pattern.quote("+") will return \+.

Because + has no significance between square brackets, you should be able to put a + unescaped within the square brackets. At that point you can also add a \\ if it makes you feel better.

Pattern pattern = Pattern.compile("(.*)(https?[:/.0-9-?a-z=_#!A-Z+]*)(.*)");
Pattern pattern = Pattern.compile("(.*)(https?[:/.0-9-?a-z=_#!A-Z\\+]*)(.*)");

See it here: http://fiddle.re/0780

Upvotes: 1

John Woo
John Woo

Reputation: 263943

just escape the quote with \, example

Pattern pattern = Pattern.compile("(.*)(https?[://.0-9-?a-z=_#!A-Z\"]*)(.*)");

Upvotes: 3

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