How to use methods of Matcher class ?

Find using Matcher

Pattern p = Pattern.compile("Java");

String candidateString = "I love Java2s. Java2s is about Java.";

Matcher matcher = p.matcher(candidateString);

while (matcher.find()) {

  System.out.print(" " + matcher.group());

}

Java Java Java

Case-insensitive flag can be used with pattern :

Pattern p = Pattern.compile("mice", Pattern.CASE_INSENSITIVE);

Reset Matcher

Pattern p = Pattern.compile("\\d");

Matcher m1 = p.matcher("01234");

while (m1.find()) {

  System.out.print(" " + m1.group());

}

m1.reset();

System.out.println("After resetting the Matcher");

while (m1.find()) {

  System.out.println(" " + m1.group());

}

0 1 2 3 4

After resetting the Matcher

0 1 2 3 4

Replace all

Pattern p = Pattern.compile("(i|I)ce");

// create the candidate String

String candidateString = "I love ice. Ice is my favorite. Ice Ice Ice.";

Matcher matcher = p.matcher(candidateString);

String tmp = matcher.replaceAll("Java");

System.out.println(tmp);

I love Java. Java is my favorite. Java Java Java.

Replace first occurance

Use replaceFirst instead of replaceAll method.

String tmp = matcher.replaceFirst("Java");

I love Java. Java is my favorite. Ice Ice Ice.

Find group

String regex = "(\\w+)(\\d\\d)(\\w+)";

Pattern pattern = Pattern.compile(regex);

String candidate = "X99SuperJava";

Matcher matcher = pattern.matcher(candidate);

matcher.find();

System.out.print(matcher.group(1));

System.out.print(matcher.group(2));

System.out.print(matcher.group(3));

X 99 SuperJava

Split

Pattern pattern = Pattern.compile("ing");

String candidate = "playingrowinglaughingsleepingweeping";

Matcher matcher = pattern.matcher(candidate);

String[] str = pattern.split(input, 4);

for(String st : str) {

  System.out.println(" " + st);

}

play row laugh sleepingweeping

Match with boolean result

String inputStr = "Computer";

String pattern = "Computer";

boolean patternMatched = Pattern.matches(pattern, inputStr);

System.out.println(patternMatched);

true