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Language: Java
Expertise: Intermediate
Aug 13, 2019
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Using REGEX and Patterns in Java

Java has a very powerful library for REGEX. A very basic usage of REGEX is being presented in the code snippet below and we can improve on this to develop complicated cases.

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

public class UnderstandingPatterns
{
   public static void main(String args[])
   {
      UnderstandingPatterns understandingPatterns = new UnderstandingPatterns();
      understandingPatterns.proceed();
   }
   
   private void proceed()
   {
      String msg = "EmpID: 1501, EmpName: Sridhar";
      String idHeader = "EmpID: ";
      String nameHeader = "EmpName: ";
      Pattern idPattern = Pattern.compile(idHeader);
      Pattern namePattern = Pattern.compile(nameHeader);
      
      Matcher idMatcher = idPattern.matcher(msg);
      Matcher nameMatcher = namePattern.matcher(msg);
      if(idMatcher.find() && nameMatcher.find()){
         int startPos = idMatcher.end() +1;
         int endPos = nameMatcher.start();
         String idValue = msg.substring(idMatcher.end(), nameMatcher.start()-2);
         String nameValue = msg.substring(nameMatcher.end());
         System.out.println("Emp ID: " + idValue);
         System.out.println("Emp Name: " + nameValue);
      }
   }
}

/*

Expected output:

[root@mypc]# java UnderstandingPatterns
Emp ID: 1501
Emp Name: Sridhar

*/ 
M S Sridhar
 
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