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Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.

Matcher.appendReplacement example

With this example we are going to demonstrate how to use Matcher.appendReplacement(StringBuffer sb, String replacement) API method to append to a StringBuffer the result of a Matcher. In short, to use a StringBuffer to append a Matcher’s result you should:

  • Compile a given String regular expression to a Pattern, using compile(string regex) API method of Pattern.
  • Use matcher(CharSequence input) API method of Pattern to create a Matcher that will match the given String input against this pattern.
  • Create a new StringBuffer.
  • Find the next subsequence of the input sequence that matches the pattern, with find() API method of Matcher and append it to the StringBuffer, implementing a non-terminal append-and-replace step, using appendReplacement(StringBuffer sb, String replacement) API method of Matcher.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class AppendReplacement {
  public static void main(String args[]) {

    Pattern pattern = Pattern.compile("(another) (test)");
    StringBuffer sb = new StringBuffer();

    String candidateString = "This is another test.";

    String replacement = "$1 AAA $2";
    Matcher m = pattern.matcher(candidateString);

    m.appendReplacement(sb, replacement);
    String msg = sb.toString();


This is another AAA test

This was an example of how to Matcher.appendReplacement(StringBuffer sb, String replacement) API method in Java.

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