Replace String in Java with regex and replaceAll

Question

Is there a simple solution to parse a String by using regex in Java?

I have to adapt a HTML page. Therefore I have to parse several strings, e.g.:

href="/browse/PJBUGS-911"
=>
href="PJBUGS-911.html"

The pattern of the strings is only different corresponding to the ID (e.g. 911). My first idea looks like this:

String input = "";
String output = input.replaceAll("href=\"/browse/PJBUGS\\-[0-9]*\"", "href=\"PJBUGS-???.html\"");

I want to replace everything except the ID. How can I do this?

Would be nice if someone can help me :)

Answer 1

You can capture substrings that were matched by your pattern, using parentheses. And then you can use the captured things in the replacement with $n where n is the number of the set of parentheses (counting opening parentheses from left to right). For your example:

String output = input.replaceAll("href=\"/browse/PJBUGS-([0-9]*)\"", "href=\"PJBUGS-1ドル.html\"");

Or if you want:

String output = input.replaceAll("href=\"/browse/(PJBUGS-[0-9]*)\"", "href=\"1ドル.html\"");

• erwingun2010: Thank you for your very quick answer and solution. Works fine :-)

Answer 2

This does not use regexp. But maybe it still solves your problem.

output = "href=\"" + input.substring(input.lastIndexOf("/")) + ".html\"";

• ean5533: Don't forget to add ".html" to the end
• Rohit Jain: Pretty simple and straightforward this is.
• ean5533: @Vulcan Yes there is. He requires it for his answer.
• Martin Ender: I believe input is not a single href="/browse/..." but a whole HTML file. Hence, the explicit mentioning of replaceAll in the question.
• bert: Thanks for the edit. And yes you're probably right @m.buettner

Answer 3

This is how I would do it:

public static void main(String[] args) 
 {
 String text = "href=\"/browse/PJBUGS-911\" blahblah href=\"/browse/PJBUGS-111\" " +
 "blahblah href=\"/browse/PJBUGS-34234\"";
 Pattern ptrn = Pattern.compile("href=\"/browse/(PJBUGS-[0-9]+?)\"");
 Matcher mtchr = ptrn.matcher(text);
 while(mtchr.find())
 {
 String match = mtchr.group(0);
 String insMatch = mtchr.group(1);
 String repl = match.replaceFirst(match, "href=\"" + insMatch + ".html\"");
 System.out.println("orig = <" + match + "> repl = <" + repl + ">");
 }
 }

This just shows the regex and replacements, not the final formatted text, which you can get by using Matcher.replaceAll:

String allRepl = mtchr.replaceAll("href=\"1ドル.html\"");

If just interested in replacing all, you don't need the loop -- I used it just for debugging/showing how regex does business.