Try this:
.....
List<File> files = getListFiles(new File("YOUR ROOT"));
....
private List<File> getListFiles(File parentDir) {
ArrayList<File> inFiles = new ArrayList<File>();
File[] files = parentDir.listFiles();
for (File file : files) {
if (file.isDirectory()) {
inFiles.addAll(getListFiles(file));
} else {
if(file.getName().endsWith(".csv")) {
inFiles.add(file);
}
}
}
return inFiles;
}
Or a variant without recursion:
private List<File> getListFiles2(File parentDir) {
List<File> inFiles = new ArrayList<>();
Queue<File> files = new LinkedList<>();
files.addAll(Arrays.asList(parentDir.listFiles()));
while (!files.isEmpty()) {
File file = files.remove();
if (file.isDirectory()) {
files.addAll(Arrays.asList(file.listFiles()));
} else if (file.getName().endsWith(".csv")) {
inFiles.add(file);
}
}
return inFiles;
}