regex
Matcher.appendReplacement example – Part 2
In this example we shall show you how to use Matcher.appendReplacement(StringBuffer sb, String replacement)
API method to append to a StringBuffer the result of a Matcher. To use a StringBuffer to append a Matcher’s result one should perform the following steps:
- 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.
- While the matcher finds the next subsequence of the input sequence that matches the pattern, with
find()
API method of Matcher get the input subsequence matched, withgroup()
API method of Matcher and append it to the StringBuffer, implementing a non-terminal append-and-replace step, usingappendReplacement(StringBuffer sb, String replacement)
API method of Matcher. - Then use
appendTail(StringBuffer sb)
API method of Matcher to implement a terminal append-and-replace step and print the result from the StringBuffer,
as described in the code snippet below.
package com.javacodegeeks.snippets.core; import java.util.regex.Matcher; import java.util.regex.Pattern; public class AppendRepl { public static void main(String[] argv) throws Exception { CharSequence input = "ab12 cd efg34 asdf 123"; String pattStr = "([a-zA-Z]+[0-9]+)"; Pattern p = Pattern.compile(pattStr); Matcher m = p.matcher(input); StringBuffer bufStr = new StringBuffer(); boolean flag = false; while ((flag = m.find())) { String rep = m.group(); m.appendReplacement(bufStr, "found<" + rep + ">"); } m.appendTail(bufStr); String result = bufStr.toString(); System.out.println(result); } }
Output:
found<ab12> cd found<efg34> asdf 123
This was an example of how to Matcher.appendReplacement(StringBuffer sb, String replacement)
API method in Java.