How to create a [] file for all * .properties in a given directory?

Question

I have a directory, C:\myDir .

this directory may contain folders and various files

How can I “loop” on this directory and create an array of files of all files with the extension .properties ?

I want to do some processing of these files, the reason for the file [] is to keep it dynamic (so additional property files will be added in the future)

I hope to do something like this:

 public static void main (String[] vargs) { // find all .properties files // //loop through property file and process { doSomething(myFile[i]); } } public void doSomething(File myfile) {} 

Answer 1

Here is the complete answer without external libraries:

 public class FileFinder{ public static List<File> findFiles(final File baseDir, final String regex){ final List<File> files = new ArrayList<File>(); scanFolder(baseDir, Pattern.compile(regex), files); return files; } private static void scanFolder(final File dir, final Pattern pattern, final List<File> files){ for(final File candidate : dir.listFiles()){ if(candidate.isDirectory()){ scanFolder(candidate, pattern, files); } else if(pattern.matcher(candidate.getName()).matches()){ files.add(candidate); } } } } 

Name it as follows:

 public static void main(String[] args){ List<File> filesAsList = FileFinder.findFiles( new File("c:\\my\\dir"), ".*\\.properties"); File[] filesAsArray = filesAsList.toArray(new File[filesAsList.size()]); } 

Answer 2

Take a look at FilenameFilter .

 final FilenameFilter filter = new FilenameFilter() { public boolean accept(final File directory, final String name) { return name.endsWith(".properties"); } }; 

Answer 3

You can use the Apache Commons IO FileUtils class for it.

 FileUtils.listFiles(File directory, String[] extensions, boolean recursive); 

Hope this helps.

Answer 4

Using commons-io FilenameUtils

 final File dir = new File("c:\\myDir"); final File[] files = dir.listFiles(new FilenameFilter() { @Override public boolean accept(final File dir, final String name) { return FilenameUtils.isExtension(name, "properties"); } }); 

Answer 5

Implemented code that returns files recursive to directories.

 import java.io.File; import java.util.ArrayList; import java.util.List; public class FileList { public static void main(String[] args) { File dir = new File("/usr/local/work_apps"); String filterExt = "properties"; List<File> fileList = new ArrayList<File>(); getFileteredFiles(dir,filterExt,fileList); for (File file : fileList) { System.out.println("FileList.main() "+file.getName()); } } /** * Get files recursively filtered by file extention. * @param dir search directory for. * @param filterExt file extention filter. * @param fileList List passed to method to be filled with file's. */ public static void getFileteredFiles(File dir,String filterExt,List<File> fileList){ if(dir.isDirectory()){ File[] files = dir.listFiles(); if(files != null && files.length > 0){ for (File file : files) { if(file.isDirectory()){ getFileteredFiles(file, filterExt, fileList); }else{ if(file.getName().endsWith("."+filterExt)){ fileList.add(file); } } } } } } } 

Answer 6

Apache commons IO has a nice class for moving file systems called DirectoryWalker . If you want to find these property files recursively, check it out.

For example, the code below will recursively find image files in a directory and return them as a list.

 import com.google.common.collect.Lists; import java.io.File; import java.io.IOException; import java.util.Collection; import java.util.List; import org.apache.commons.io.DirectoryWalker; import org.apache.commons.io.IOCase; import org.apache.commons.io.filefilter.AndFileFilter; import org.apache.commons.io.filefilter.DirectoryFileFilter; import org.apache.commons.io.filefilter.HiddenFileFilter; import org.apache.commons.io.filefilter.IOFileFilter; import org.apache.commons.io.filefilter.NotFileFilter; import org.apache.commons.io.filefilter.OrFileFilter; import org.apache.commons.io.filefilter.PrefixFileFilter; import org.apache.commons.io.filefilter.SuffixFileFilter; class SourceImageFinder extends DirectoryWalker { public SourceImageFinder() { // visible directories and image files super(new AndFileFilter(notHiddenFileFilter(), new OrFileFilter(imageFileFilter(), DirectoryFileFilter.INSTANCE)), -1); } public List<File> findSourceImages(File directory) { List<File> results = Lists.newArrayList(); try { walk(directory, results); } catch (IOException ex) { throw new RuntimeException("Problem finding images", ex); } return results; } @Override protected void handleFile(File file, int depth, Collection results) throws IOException { results.add(file); } private static IOFileFilter notHiddenFileFilter() { // HiddenFileFilter.HIDDEN doesn't exclude files starting with '.' on Windows but I want to. return new NotFileFilter(new OrFileFilter(HiddenFileFilter.HIDDEN, new PrefixFileFilter("."))); } private static IOFileFilter imageFileFilter() { return new SuffixFileFilter(new String[]{"png", "jpg", "jpeg", "gif", "bmp", "tif", "tiff"}, IOCase.INSENSITIVE); } }