Iterating through a directory in java

If you are using Java 7, then you need to take a look at NIO.2.

Specifically, take a look at the Listing a Directory's Contents section.

Path dir = Paths.get("/directory/path"); try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) { for (Path file: stream) { getDoubleByteArrayOfFile(file.getFileName(), someRegion); } } catch (IOException | DirectoryIteratorException x) { // IOException can never be thrown by the iteration. // In this snippet, it can only be thrown by newDirectoryStream. System.err.println(x); } 

Here is a quick example that may help:

private ArrayList<byte[][]> getDoubleByteArrayOfDirectory(String dirName, Region region) throws IOException { ArrayList<byte[][]> results = new ArrayList<byte[][]>(); File directory = new File(dirName); if (!directory.isDirectory()) return null //or handle however you wish for (File file : directory.listFiles()) { results.add(getDoubleByteArrayOfFile(file.getName()), region); } return results; } 

Not exactly what you asked for since it's wrapping your old method rather than re-writing it, but I find it a bit cleaner this way, and leaves you with the option of still processing a single file. Be sure to tweak the return type and how to handle the region based on your actual requirements (hard to tell from the question).

It is rather simple, using the File#listFiles() which returns a list of files in the specified File, which must be a directory. To make sure that the File is a directory, simply use File#isDirectory(). The problem occurs where you decide how to return the byte buffer. Since the method returns a 2d buffer, it is necessary to use a 3d byte buffer array, or in this case a List seems to me like the best choice since an unknown number of files will exist in the directory in question.

 private List getDoubleByteArrayOfDirectory(String directory, Region region) throws IOException { File directoryFile = new File(directory); if(!directoryFile.isDirectory()) { throw new IllegalArgumentException("path must be a directory"); } List results = new ArrayList(); for(File temp : directoryFile.listFiles()) { if(temp.isDirectory()) { results.addAll(getDoubleByteArrayOfDirectory(temp.getPath(), region)); }else { results.add(getDoubleByteArrayOfFile(temp.getPath(), region)); } } return results; } 

You can, see the list and listFiles documentation for how to do this.

We can use recursion to process a directory with subdirectories also. Here I am deleting file one by one, you can call any other function to process it.

public static void recursiveProcess(File file) { //to end the recursive loop if (!file.exists()) return; //if directory, go inside and call recursively if (file.isDirectory()) { for (File f : file.listFiles()) { //call recursively recursiveProcess(f); } } //call processing function, for example here I am deleting file.delete(); System.out.println("Deleted (Processed) file/folder: "+file.getAbsolutePath()); }