How to check a file if exists with wildcard in Java?

Question

I have a directory, and inside it are files are named \"a_id_XXX.zip\".

How do check if a file exists given an id and File dir

Answer 1

This solution generalizes on Bohemian's answer. It uses regular expressions and also replaces the inner class with Java 8 lambda expressions. Thanks @Bohemian for the original implementation.

import java.io.File;

public class FileFinder {
    public static void main(String[] args){
        File directory = new File("D:\\tmp");
        String id = "20140430104033";
        for (File f : findFilenamesWithId(id, directory)){
            System.out.println(f.getAbsoluteFile());
        }
    }

    /** Finds files in the specified directory whose names are formatted 
        as "a_id_ID.zip" */
    public static File[] findFilenamesWithId(String ID, File dir) {
        return findFilenamesMatchingRegex("^a_id_" + ID + "\\.zip$", dir);
    }

    /** Finds files in the specified directory whose names match regex */
    public static File[] findFilenamesMatchingRegex(String regex, File dir) {
        return dir.listFiles(file -> file.getName().matches(regex));
    }
}