Friday, September 24, 2021

How to Use Regular Expression as a Substitute of endsWith() Method in Java?

Oracle Java Exam Prep, Oracle Java Preparation, Oracle Java Guides, Core Java, Java Learning

So primarily discuss what is endsWith() method is, so it is a method of String class that checks whether the string ends with a specified suffix. This method returns a boolean value true or false.

Syntax:

public boolean endsWith(String suff)      

Parameter: specified suffix part  

Return: Boolean value, here in java we only have true and false.

Methods:

We can use Regular Expression / Matches as a substitute for startWith() method in Java

1. Using Regular Expression

2. Using Matches 

Method 1: Using Regular Expression

Regular Expressions or Regex (in short) is an API for defining String patterns that can be used for searching, manipulating, and editing a string in Java. Email validation and passwords are a few areas of strings where Regex is widely used to define the constraints. Regular Expressions are provided under java.util.regex package. This consists of 3 classes and 1 interface. The java.util.regex package primarily consists of the following three classes as depicted below in tabular format as follows:

◉ Pattern

◉ Matcher

◉ PatternSyntaxException

Example

// Java Program to Illustrate use of Regular Expression

// as substitute of endsWith() method

// Importing required classes

import java.util.regex.Matcher;

import java.util.regex.Pattern;

// Main class

public class Java {

// Main driver method

public static void main(String args[])

{

// Declaring and initialising string

String Str = new String("Welcome to oraclejavacertified");

// Display message

System.out.print(

"Check whether string ends with Welcome using endsWith : ");

// Using endWith() method

System.out.println(Str.endsWith("Java"));

// Creating Pattern and matcher classes object

Pattern pattern = Pattern.compile(".*Java");

Matcher m = pattern.matcher(Str);

// Checking whether string ends with specific word

// or nor and returning the boolean value

// using ? operator and find() method

System.out.print(

"Check whether string ends with Welcome using Regex: ");

System.out.println(m.find() ? "true" : "false");

}

}

Output

Check whether string ends with Welcome using endsWith : true
Check whether string ends with Welcome using Regex: true

Method 2: Using Matches

String.matches() method tells whether or not this string matches the given regular expression. An invocation of this method of the form str.matches(regex) yields exactly the same result as the expression Pattern.matches(regex, str).

Syntax:

public boolean matches(String regex);

Parameters: The regular expression to which this string is to be matched.

Return Value: This method returns true if, and only if, this string matches the given regular expression.

Example

// Java Program to Illustrate use of Matches
// as substitute of endsWith() method

// Importing all utility classes
import java.util.*;

// Main class
public class Java {

// Main driver method
public static void main(String args[])
{

// Initialising String
String Str = new String("Welcome to oraclejavacertified");

// Display message for better readibility
System.out.print(
"Check whether string starts with Welcome using endsWith : ");
// Using endsWith() to end with specific word
System.out.println(Str.endsWith("Java"));

// Display message for better readibility
System.out.print(
"Check whether string starts with Welcome using Matches: ");
// Now checking whether it matches with
// above defined specific word
System.out.println(Str.matches("(.*)Java"));
}
}

Output

Check whether string starts with Welcome using endsWith : true
Check whether string starts with Welcome using Matches: true

Source: geeksforgeeks.org

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