Replacing contents of a String using replaceFirst()

Question

I have a file with below contents:

Test:Line1@line.com
Goal:[[goal]]
Email:[[email]]
Further Text

Below is code to get the file contents into a StringBuffer and get the value into the String output.

Path signature = Paths.get("signature.txt");
StringBuffer sigBuffer = new StringBuffer();
String line = null;
BufferedReader reader = null;
try {
 reader = Files.newBufferedReader(signature);
 while ((line = reader.readLine()) != null) {
   sigBuffer.append(line);
   sigBuffer.append("\n");
 }
 String output = sigBuffer.toString();
} catch...finally...

I want to replace the [[goal]] with Goal A AND [[email]] with email@mail.com

I tried this:

String regExp = "\\[\\[[a-z_]*\\]\\]";
output.replaceFirst(regExp, "Goal A");
output.replaceFirst(regExp, "email@mail.com");

But my output is still:

Test:Line1@line.com
Goal:[[goal]]
Email:[[email]]
Further Text

http://stackoverflow.com/questions/5658794/how-to-use-replacefirst-to-replace?rq=1 — Erik Pragt, Mar 21 '16 at 05:23

score 2 · Accepted Answer · answered Mar 21 '16 at 05:23

2

String is immutable. You need to assign the result of the replaceFirst call back to the variable.

output = output.replaceFirst(....)

answered Mar 21 '16 at 05:23

Andy Turner

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Maybe downvoted because there are dupes, which themselves have dupes ad nauseum, for this problem – Bohemian Mar 21 '16 at 05:29

Replacing contents of a String using replaceFirst()

1 Answers1