从 RegEx String 获取资源

Question

After hours of searching and trying and failing, I decided to ask my question here. I want to replace :(.+?): in a string with the resource loaded from /src. For example if I would type in ":foo.bar:" it would replace it with this.getClass().getResource("foo.bar"); .

My concrete situation: I have a little chat application using smileys, located in the "smileys"-folder in "src". If a user types ":foo:", it should get the full URL of "smileys/foo.png", if the file exists ( this.getClass().getResource("smileys/foo.png"); in this case) and put it into tags. So for example if a user types "foo :bar:", it should be converted into "foo C:/<...>/smileys/bar.png".

How could I do this? Thank you for your answers,

Benni

Answer 1

They explain how to do this in the documentation provided by oracle.This normally to all regex in all languages though, not just java.

" A backreference is specified in the regular expression as a backslash () followed by a digit indicating the number of the group to be recalled. For example, the expression (\\d\\d) defines one capturing group matching two digits in a row, which can be recalled later in the expression via the backreference \\1.

To match any 2 digits, followed by the exact same two digits, you would use (\\d\\d)\\1 as the regular expression:

Enter your regex: (\d\d)\1

Enter input string to search: 1212

I found the text "1212" starting at index 0 and ending at index 4.

If you change the last two digits the match will fail:

Enter your regex: (\d\d)\1

Enter input string to search: 1234
No match found.

For nested capturing groups, backreferencing works in exactly the same way: Specify a backslash followed by the number of the group to be recalled."

https://docs.oracle.com/javase/tutorial/essential/regex/groups.html

Answer 2

Below code will do what you want:

String s = "x = :foo.bar: ;";
String res = s.replaceAll(":(.+?):","this.getClass().getResource(\"$1\")");
System.out.println(res);

prints

x = this.getClass().getResource("foo.bar") ;