JAVA EE: How to write a regex to validate the image name

Thursday, 21 December 2017

How to write a regex to validate the image name | Regex in java

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How to write a regex to validate the image name | Regex in java

ImageValidator.java

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/**

 * 

 * How to validate image file extension with regular expression

 *

 */

public class ImageValidator

{

    private Pattern pattern;

    private Matcher matcher;

    private static final String IMAGE_NAME_REGEX = "([^\\s]+(\\.(?i)(jpg|png|gif|bmp))$)";

    public ImageValidator()

    {

        pattern = Pattern.compile(IMAGE_NAME_REGEX);

    }

    /**

     * Validate image with regular expression

     * 

     * @param imageName imageName for validation

     * @return true valid imageName, false invalid imageName

     */

    public boolean validate(final String imageName)

    {

        matcher = pattern.matcher(imageName);

        return matcher.matches();

    }

}

RegexDemo.java

import java.util.Arrays;

import java.util.List;

/**

 * 

 * How to validate image file extension with regular expression

 *

 */

public class RegexDemo

{

    public static void main(String[] args)

    {

        List<String> validImageNameList = Arrays.asList("cat.jpg", "cat.gif",

                "cat.png", "cat.bmp", "dog.JPG", "dog.GIF", "dog.PNG",

                "dog.BMP","rose.JpG", "rose.gIF", "rose.PNg",

                "rose.BMp");

        ImageValidator imageValidator = new ImageValidator();

        for (String imageName : validImageNameList)

        {

            System.out.println(imageName + " is Valid? = " + imageValidator.validate(imageName));

        }

        System.out.println("--------------------------------------");

        List<String> inValidImageNameList = Arrays.asList(".jpg", " .gif","dog.txt","jpg");

        for (String imageName : inValidImageNameList)

        {

            System.out.println(imageName + " is Valid? = " + imageValidator.validate(imageName));

        }

    }

}

Output

cat.jpg is Valid? = true

cat.gif is Valid? = true

cat.png is Valid? = true

cat.bmp is Valid? = true

dog.JPG is Valid? = true

dog.GIF is Valid? = true

dog.PNG is Valid? = true

dog.BMP is Valid? = true

rose.JpG is Valid? = true

rose.gIF is Valid? = true

rose.PNg is Valid? = true

rose.BMp is Valid? = true

--------------------------------------

.jpg is Valid? = false

 .gif is Valid? = false

dog.txt is Valid? = false

jpg is Valid? = false