Develop Reference

Java recursion print directory subdirectory files

I'm trying to loop through a folder and list all files with a specific file ending. I'm trying to solve this problem with a recursive method but I'm not getting anywhere.
private int counter = 0;
public void printAllJavaFiles(File directory) {
printFile(directory);
File[] subDirectories = directory.listFiles();
for (File file : subDirectories) {
printAllJavaFiles(file);
}
}
private void printFile(File file) {
// Get file extension
String fileExtension = "";
int i = file.getName().lastIndexOf('.');
if (i >= 0) {
fileExtension = file.getName().substring(i + 1);
}
if (fileExtension.equals("java")) {
System.out.println("File: " + file.getName() + " Size: " + file.length());
}
}
Any suggestions? I really have no idea how to go up and down in the directory structure. It just enters the first folder and once it's done listing it's files it throws a nullpointerexception.

You should use the File.isDirectory() method. Like this:
public void printAllJavaFiles(File directory) {
if (directory.isDirectory()) {
File[] subDirectories = directory.listFiles();
for (File file : subDirectories) {
printAllJavaFiles(file);
}
}else {
printFile(directory);
}
}
Documentation on that method here: https://docs.oracle.com/javase/7/docs/api/java/io/File.html#isDirectory()
The idea is that for every file you check if it is a folder, if so, make the recursive call. If not, simply print the file.

Java nio move folder with content throws exception [duplicate]

How do you move a file from one location to another? When I run my program any file created in that location automatically moves to the specified location. How do I know which file is moved?

myFile.renameTo(new File("/the/new/place/newName.file"));
File#renameTo does that (it can not only rename, but also move between directories, at least on the same file system).
Renames the file denoted by this abstract pathname.
Many aspects of the behavior of this method are inherently platform-dependent: The rename operation might not be able to move a file from one filesystem to another, it might not be atomic, and it might not succeed if a file with the destination abstract pathname already exists. The return value should always be checked to make sure that the rename operation was successful.
If you need a more comprehensive solution (such as wanting to move the file between disks), look at Apache Commons FileUtils#moveFile

With Java 7 or newer you can use Files.move(from, to, CopyOption... options).
E.g.
Files.move(Paths.get("/foo.txt"), Paths.get("bar.txt"), StandardCopyOption.REPLACE_EXISTING);
See the Files documentation for more details

Java 6
public boolean moveFile(String sourcePath, String targetPath) {
File fileToMove = new File(sourcePath);
return fileToMove.renameTo(new File(targetPath));
}
Java 7 (Using NIO)
public boolean moveFile(String sourcePath, String targetPath) {
boolean fileMoved = true;
try {
Files.move(Paths.get(sourcePath), Paths.get(targetPath), StandardCopyOption.REPLACE_EXISTING);
} catch (Exception e) {
fileMoved = false;
e.printStackTrace();
}
return fileMoved;
}

File.renameTo from Java IO can be used to move a file in Java. Also see this SO question.

To move a file you could also use Jakarta Commons IOs FileUtils.moveFile
On error it throws an IOException, so when no exception is thrown you know that that the file was moved.

Just add the source and destination folder paths.
It will move all the files and folder from source folder to
destination folder.
File destinationFolder = new File("");
File sourceFolder = new File("");
if (!destinationFolder.exists())
{
destinationFolder.mkdirs();
}
// Check weather source exists and it is folder.
if (sourceFolder.exists() && sourceFolder.isDirectory())
{
// Get list of the files and iterate over them
File[] listOfFiles = sourceFolder.listFiles();
if (listOfFiles != null)
{
for (File child : listOfFiles )
{
// Move files to destination folder
child.renameTo(new File(destinationFolder + "\\" + child.getName()));
}
// Add if you want to delete the source folder
sourceFolder.delete();
}
}
else
{
System.out.println(sourceFolder + " Folder does not exists");
}

Files.move(source, target, REPLACE_EXISTING);
You can use the Files object
Read more about Files

You could execute an external tool for that task (like copy in windows environments) but, to keep the code portable, the general approach is to:
read the source file into memory
write the content to a file at the new location
delete the source file
File#renameTo will work as long as source and target location are on the same volume. Personally I'd avoid using it to move files to different folders.

Try this :-
boolean success = file.renameTo(new File(Destdir, file.getName()));

Wrote this method to do this very thing on my own project only with the replace file if existing logic in it.
// we use the older file i/o operations for this rather than the newer jdk7+ Files.move() operation
private boolean moveFileToDirectory(File sourceFile, String targetPath) {
File tDir = new File(targetPath);
if (tDir.exists()) {
String newFilePath = targetPath+File.separator+sourceFile.getName();
File movedFile = new File(newFilePath);
if (movedFile.exists())
movedFile.delete();
return sourceFile.renameTo(new File(newFilePath));
} else {
LOG.warn("unable to move file "+sourceFile.getName()+" to directory "+targetPath+" -> target directory does not exist");
return false;
}
}

Please try this.
private boolean filemovetoanotherfolder(String sourcefolder, String destinationfolder, String filename) {
boolean ismove = false;
InputStream inStream = null;
OutputStream outStream = null;
try {
File afile = new File(sourcefolder + filename);
File bfile = new File(destinationfolder + filename);
inStream = new FileInputStream(afile);
outStream = new FileOutputStream(bfile);
byte[] buffer = new byte[1024 * 4];
int length;
// copy the file content in bytes
while ((length = inStream.read(buffer)) > 0) {
outStream.write(buffer, 0, length);
}
// delete the original file
afile.delete();
ismove = true;
System.out.println("File is copied successful!");
} catch (IOException e) {
e.printStackTrace();
}finally{
inStream.close();
outStream.close();
}
return ismove;
}

Moving file from one directory to another and delete from source directory using java

I am trying to move files from one directory to another delete that file from source directory after moving.
for (File file : files) {
if (file != null) {
boolean status = moveFile(file, filePath, name, docGroupId);
if (status) {
//some operations....
}
}
}
public static boolean moveFile(final File file, final String filePath, final String groupName, Integer docGroupId) {
// TODO Auto-generated method stub
String selectedDirectory = filePath + File.separator + groupName;
InputStream in = null;
OutputStream out = null;
try {
if (!file.isDirectory()) {
File dir = new File(selectedDirectory);
if (!dir.exists()) {
dir.mkdirs();
}
String newFilString = dir.getAbsolutePath() +
File.separator + file.getName();
File newFile = new File(newFilString);
in = new FileInputStream(file);
out = new FileOutputStream(newFile);
byte[] moveBuff = new byte[1024];
int butesRead;
while ((butesRead = in.read(moveBuff)) > 0) {
out.write(moveBuff, 0, butesRead);
}
}
in.close();
out.close();
if(file.delete())
return true;
} catch (Exception e) {
return false;
}
}
The program works on Linux-Ubuntu and all files are moved to another directory and deleted from source directory, but in Windows system all files are moved but failed to delete one or two files from source directory. Please note that while debugging the program is working fine.

Consider using Files.delete instead of File.delete. The javadoc says:
Note that the Files class defines the delete method to throw an IOException when a file cannot be deleted. This is useful for error reporting and to diagnose why a file cannot be deleted.
This should provide the information necessary to diagnose the problem.

So, if problem comes with delete, possible explanations:
you do file.delete() on every files and directories. How do you know the directory is empty ? If not, it will fail, then what happen to next instructions ?
file deletion is OS-dependant. On Windows, you can have many security issues, depending on which user, which rights, which location. You should check with a file-delete-alone program;
last: files can be locked by other programs (even explorer), it is also OS-dependant.

You don't need any of this if the source and target are in the same file system. Just use File.renameTo().

Download entire FTP directory in Java (Apache Net Commons)

I am trying to recursively iterate through the entire root directory that I arrive at after login to the FTP server.
I am able to connect, all I really want to do from there is recurse through the entire structure and and download each file and folder and have it in the same structure as it is on the FTP. What I have so far is a working download method, it goes to the server and gets my entire structure of files, which is brilliant, except it fails on the first attempt, then works the second time around. The error I get is as follows:
java.io.FileNotFoundException: output-directory\test\testFile.png
(The system cannot find the path specified)
I managed to do upload functionality of a directory that I have locally, but can't quite get downloading to work, after numerous attempts I really need some help.
public static void download(String filename, String base)
{
File basedir = new File(base);
basedir.mkdirs();
try
{
FTPFile[] ftpFiles = ftpClient.listFiles();
for (FTPFile file : ftpFiles)
{
if (!file.getName().equals(".") && !file.getName().equals("..")) {
// If Dealing with a directory, change to it and call the function again
if (file.isDirectory())
{
// Change working Directory to this directory.
ftpClient.changeWorkingDirectory(file.getName());
// Recursive call to this method.
download(ftpClient.printWorkingDirectory(), base);
// Create the directory locally - in the right place
File newDir = new File (base + "/" + ftpClient.printWorkingDirectory());
newDir.mkdirs();
// Come back out to the parent level.
ftpClient.changeToParentDirectory();
}
else
{
ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
String remoteFile1 = ftpClient.printWorkingDirectory() + "/" + file.getName();
File downloadFile1 = new File(base + "/" + ftpClient.printWorkingDirectory() + "/" + file.getName());
OutputStream outputStream1 = new BufferedOutputStream(new FileOutputStream(downloadFile1));
boolean success = ftpClient.retrieveFile(remoteFile1, outputStream1);
outputStream1.close();
}
}
}
}
catch(IOException ex)
{
System.out.println(ex);
}
}

Your problem (well, your current problem after we got rid of the . and .. and you got past the binary issue) is that you are doing the recursion step before calling newDir.mkdirs().
So suppose you have a tree like
.
..
someDir
.
..
someFile.txt
someOtherDir
.
..
someOtherFile.png
What you do is skip the dot files, see that someDir is a directory, then immediately go inside it, skip its dot files, and see someFile.txt, and process it. You have not created someDir locally as yet, so you get an exception.
Your exception handler does not stop execution, so control goes back to the upper level of the recursion. At this point it creates the directory.
So next time you run your program, the local someDir directory is already created from the previous run, and you see no problem.
Basically, you should change your code to:
if (file.isDirectory())
{
// Change working Directory to this directory.
ftpClient.changeWorkingDirectory(file.getName());
// Create the directory locally - in the right place
File newDir = new File (base + "/" + ftpClient.printWorkingDirectory());
newDir.mkdirs();
// Recursive call to this method.
download(ftpClient.printWorkingDirectory(), base);
// Come back out to the parent level.
ftpClient.changeToParentDirectory();
}

A complete standalone code to download all files recursively from an FTP folder:
private static void downloadFolder(
FTPClient ftpClient, String remotePath, String localPath) throws IOException
{
System.out.println("Downloading folder " + remotePath + " to " + localPath);
FTPFile[] remoteFiles = ftpClient.listFiles(remotePath);
for (FTPFile remoteFile : remoteFiles)
{
if (!remoteFile.getName().equals(".") && !remoteFile.getName().equals(".."))
{
String remoteFilePath = remotePath + "/" + remoteFile.getName();
String localFilePath = localPath + "/" + remoteFile.getName();
if (remoteFile.isDirectory())
{
new File(localFilePath).mkdirs();
downloadFolder(ftpClient, remoteFilePath, localFilePath);
}
else
{
System.out.println("Downloading file " + remoteFilePath + " to " +
localFilePath);
OutputStream outputStream =
new BufferedOutputStream(new FileOutputStream(localFilePath));
if (!ftpClient.retrieveFile(remoteFilePath, outputStream))
{
System.out.println("Failed to download file " + remoteFilePath);
}
outputStream.close();
}
}
}
}

List of files inside a zip folder and its subfolder

I am looking a way to get the list of files inside a zip file. I created a method to get the list of files inside a directory but I am also looking a way to get files inside a zip as well instead of showing just zip file.
here is my method:
public ArrayList<String> listFiles(File f, String min, String max) {
try {
// parse input strings into date format
Date minDate = sdf.parse(min);
Date maxDate = sdf.parse(max);
//
File[] list = f.listFiles();
for (File file : list) {
double bytes = file.length();
double kilobytes = (bytes / 1024);
if (file.isFile()) {
String fileDateString = sdf.format(file.lastModified());
Date fileDate = sdf.parse(fileDateString);
if (fileDate.after(minDate) && fileDate.before(maxDate)) {
lss.add("'" + file.getAbsolutePath() +
"'" + " Size KB:" + kilobytes + " Last Modified: " +
sdf.format(file.lastModified()));
}
} else if (file.isDirectory()) {
listFiles(file.getAbsoluteFile(), min, max);
}
}
} catch (Exception e) {
e.getMessage();
}
return lss;
}

After having searched for a better answer for a while, I finally found a better way to do this. You can actually do the same thing in a more generic way using the Java NIO API (Since Java 7).
// this is the URI of the Zip file itself
URI zipUri = ...;
FileSystem zipFs = FileSystems.newFileSystem(zipUri, Collections.emptyMap());
// The path within the zip file you want to start from
Path root = zipFs.getPath("/");
Files.walkFileTree(root, new SimpleFileVisitor<Path>() {
#Override
public FileVisitResult visitFile(Path path, BasicFileAttributes attrs) throws IOException {
// You can do anything you want with the path here
System.out.println(path);
// the BasicFileAttributes object has lots of useful meta data
// like file size, last modified date, etc...
return FileVisitResult.CONTINUE;
}
// The FileVisitor interface has more methods that
// are useful for handling directories.
});
This approach has the advantage that you can travers ANY file system this way: your normal windows or Unix filesystem, the file system contain contained within a zip or a jar, or any other really.
You can then trivially read the contents of any Path via the Files class, using methods like Files.copy(), File.readAllLines(), File.readAllBytes(), etc...

You can use ZipFile.entries() method to read the list of files via iteration as below:
File[] fList = directory.listFiles();
for (File file : fList)
{
ZipFile myZipFile = new ZipFile(fList.getName());
Enumeration zipEntries = myZipFile.entries();
while (zipEntries.hasMoreElements())
{
System.out.println(((ZipEntry) zipEntries.nextElement()).getName());
// you can do what ever you want on each zip file
}
}