Java Regex | Java Regex Example | Java Regex In Hindi

Java Regex

The Java Regex or Regular Expression is an API to define a pattern for searching or manipulating strings.

It is widely used to define the constraint on strings such as password and email validation. After learning Java regex tutorial, you will be able to test your regular expressions by the Java Regex Tester Tool.Java Regex API provides 1 interface and 3 classes in java.util.regex package.

Fig: Java Regex

java.util.regex package

The Matcher and Pattern classes provide the facility of Java regular expression. The java.util.regex package provides following classes and interfaces for regular expressions.

1.    MatchResult interface

2.    Matcher class

3.    Pattern class

4.    PatternSyntaxException class

Example of java Regex

     import java.util.regex.*;  

     public class RegexExample1{  

     public static void main(String args[]){  

     //1st way  

     Pattern p = Pattern.compile(".s");//. represents single character  

     Matcher m = p.matcher("as");  

    boolean b = m.matches();  

  

     //2nd way  

    boolean b2=Pattern.compile(".s").matcher("as").matches();  

  

     //3rd way  

    boolean b3 = Pattern.matches(".s", "as");  

  

      System.out.println(b+" "+b2+" "+b3);   

      } }  

    

     Output:

             true  true  true