java regex pattern validate image file extension

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Regular expression image file extension pattern

([^\s]+(\.(?i)(jpg|png|gif|bmp))$)

This regular expression refers to a pattern which must have 1 or more strings (but not white space), follow by dot “.” and string end in “jpg” or “png” or “gif” or “bmp”, and the file extensive is case-insensitive.

Example

package com.w3schools;
 
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class RegexTest {
	private static final String PATTERN = "([^\\s]+(\\.(?i)(jpg|png|gif|bmp))$)";
	public static void main(String args[]){ 
		List<String> values = new ArrayList<String>();	
		values.add("jai.jpg"); 
		values.add("java.png"); 
		values.add("a.txt");
		values.add("a.mp3");
 
		Pattern pattern = Pattern.compile(PATTERN);
		for (String value : values){
		  Matcher matcher = pattern.matcher(value);
		  if(matcher.matches()){
			  System.out.println("File "+ value +" is valid image");
		  }else{
			  System.out.println("File "+ value +" is invalid image");
		  }		  
		}
	}
}