Filter image files from a folder in Java
Let’s see how to filter-out only image files from a directory in Java. We will write code to iterate through all the files present in a directory, and then filter out only the image files by their extension. In the following example snippet, .jpg, .png, .gif and .webp images will be selected from the given folder.
- Pass the directory from which images should be found as the parameter
- Specify the image extension for the required images in the list supportedImageExtensions
private List<File> getAllImageFilesFromFolder(File directory) {
//Get all the files from the folder
File[] allFiles = directory.listFiles();
if (allFiles == null || allFiles.length == 0) {
throw new RuntimeException("No files present in the directory: " + directory.getAbsolutePath());
}
//Set the required image extensions here.
List<String> supportedImageExtensions = Arrays.asList("jpg", "png", "gif", "webp");
//Filter out only image files
List<File> acceptedImages = new ArrayList<>();
for (File file : allFiles) {
//Parse the file extension
String fileExtension = file.getName().substring(file.getName().lastIndexOf(".") + 1);
//Check if the extension is listed in the supportedImageExtensions
if (supportedImageExtensions.stream().anyMatch(fileExtension::equalsIgnoreCase)) {
//Add the image to the filtered list
acceptedImages.add(file);
}
}
//Return the filtered images
return acceptedImages;
}
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