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How to differentiate between an empty file that has no extension and a directory in java?

Let's suppose I have a zip file containing two elements: elem1 (created by linux command touch elem1) and elem2 (created by linux command mkdir elem2)
Now, in java, I use the following code to extract the content of the zip
// ...
// Suppose we have a valid inputStream on a zip file
// ...
ZipInputStream zipInputStream = new ZipInputStream(inputStream);
ZipEntry entry = zipInputStream.getNextEntry();
while (entry != null) {
int entrySize = (int) entry.getSize();
File file = Paths.get(extractPath).resolve(entry.getName()).toFile();
if (/*Condition to detect a directory*/) {
System.out.println("This is a directory");
FileUtils.forceMkdir(file);
} else if (/*Condition to detect an empty file*/) {
System.out.println("This is an empty file");
} else {
System.out.println("This is something else");
}
entry = zipInputStream.getNextEntry();
}
I would like to specify the right conditions to detect whether entry is a directory, or an empty file without extension. Knowing that these entries are still in memory and do not exist on the filesystem, the command file.isDirectory() always returns false; so I cannot not use it to check for directory.
Any ideas please ?

I created both an empty folder and an empty file without extension and evaluated them with the code below:
public static void main(String[] args) {
String path = System.getProperty("user.home") + File.separator + "Desktop" + File.separator;
File file = new File(path + "EmptyFile");
File folder = new File (path + "EmptyFolder");
System.out.println("Is 'folder' a folder? " + (Files.isDirectory(folder.toPath())? "Yes" : "No" ));
System.out.println("Is 'file' a folder? " + (Files.isDirectory(file.toPath())? "Yes" : "No" ));
}
The (not surprising) result:
Is 'folder' a folder? Yes
Is 'file' a folder? No
The reason why this works is because the function Files.isDirectory(...) looks in the file attributes set by the Operating System to determine whether the item being examined is a "File folder" or simply a "file". My assumption is that Zip programs do not contain such metadata (not even Windows zip). Therefore, "isDirectory" test cannot be performed using the Files.isDirectory(...) function. My quick research discovered that, the way to do this (and I am kind of shocked) is by examining the file name and check to see if the name ends with the file separator. In fact, this is how ZipEntry.isDirectory() works.
Attempting to zip an empty folder is not allowed for Windows zip (maybe allowed with other software?). However, I was able to include empty directories with 7-zip. That wasn't the only difference. The isDirectory() test failed when the zip was created with Windows zip because the file was skipped altogether. So, in order for this to work, create the zip file with zip software other than the one that comes with Windows. Then,
public static void main(String[] args) throws IOException {
String path = System.getProperty("user.home") + File.separator + "Desktop" + File.separator;
FileInputStream inputStream = new FileInputStream(path + "Desktop.zip");
ZipInputStream zipInputStream = new ZipInputStream(inputStream);
ZipEntry entry = zipInputStream.getNextEntry();
while (entry != null) {
File file = Paths.get(entry.getName()).toFile();
if (entry.isDirectory()) {
System.out.println(entry.getName() + " is a directory");
} else if (file.getName().endsWith(".lnk")) {
System.out.println(file.getName() + " is a shortcut");
} else {
System.out.println(entry.getName() + " is a file");
}
entry = zipInputStream.getNextEntry();
}
zipInputStream.close();
}
Outputs for me:
EmptyFile is a file
EmptyFolder/ is a directory
How We Test Wireless Routers _ PCMag_files/ is a directory
How We Test Wireless Routers _ PCMag_files/00hSyhn9j5PNrcOot1tMzz9.1578945749.fit_lim.size_100x100.png is a file
...
etc
One last note... obviously, if a ZipEntry is not a directory, it is a file. Therefore, no else if is needed. That is, unless you would like to make a distinction between file types. In the example above, I wanted to check if a particular file was a shortcut. Just keep in mind that this is not necessary. The logic should only test entries for isDirectory and if the test fails, it is simply a file.

Delete and move file to a directory in java

I am trying to move a file from one directory to another using renameTo() in java, however renameTo doesnt work (doesnt rename and move the file). Basically, I want to delete the file in one first with same file name, then copy a file from anoter directory to the same location where I deleted the file originally, then copy the new one with same name.
//filePath = location of original file with file name appended. ex: C:\Dir\file.txt
//tempPath = Location of file that I want to replace it to file file without the file name. ex: C:\AnotherDir
int pos = filePath.indexOf("C:\\Dir\\file.txt");
//Parse out only the path, so just C:\\Dir
String newFilePath = filePath.substring(0,pos-1);
//I want to delete the original file
File deletefile = new File(newFilePath,"file.txt");
if (deletefile.exists()) {
success = deletefile.delete();
}
//There is file already exists in the directory, but I am just appending .tmp at the end
File newFile = new File(tempPath + "file.txt" + ".tmp");
//Create original file again with same name.
File oldFile = new File(newFilePath, "file.txt");
success = oldFile.renameTo(newFile); // This doesnt work.
Can you tell me what I am doing wrong?
Thanks for your help.

You need to escape the backslashes in the string literal: "C:\\Dir\\file.txt". Or use File.separator to construct the path.
Additionally, ensure newFile's path is constructed properly:
File newFile = new File(tempPath + File.separator + "file.txt" + ".tmp");
//^^^^^^^^^^^^^^^^
as the commments in the posted code (...ex: C:\AnotherDir) indicate that tempPath has no trailing slash character.

I have moved files to the destination directory and after moving deleted those moved files from source folder, in three ways, and at last am using the 3rd approach in my project.
1st approach:
File folder = new File("SourceDirectory_Path");
File[] listOfFiles = folder.listFiles();
for (int i = 0; i < listOfFiles.length; i++) {
Files.move(Paths.get("SourceDirectory_Path"+listOfFiles[i].getName()), Paths.get("DestinationDerectory_Path"+listOfFiles[i].getName()));
}
System.out.println("SUCCESS");
2nd approach:
Path sourceDir = Paths.get("SourceDirectory_Path");
Path destinationDir = Paths.get("DestinationDerectory_Path");
try(DirectoryStream<Path> directoryStream = Files.newDirectoryStream(sourceDir)){
for (Path path : directoryStream) {
File d1 = sourceDir.resolve(path.getFileName()).toFile();
File d2 = destinationDir.resolve(path.getFileName()).toFile();
File oldFile = path.toFile();
if(oldFile.renameTo(d2)){
System.out.println("Moved");
}else{
System.out.println("Not Moved");
}
}
}catch (Exception e) {
e.printStackTrace();
}
3rd approach:
Path sourceDirectory= Paths.get(SOURCE_FILE_PATH);
Path destinationDirectory = Paths.get(SOURCE_FILE_MOVE_PATH);
try (DirectoryStream<Path> directoryStream = Files.newDirectoryStream(sourceDirectory)) {
for (Path path : directoryStream) {
Path dpath = destinationDirectory .resolve(path.getFileName());
Files.move(path, dpath, StandardCopyOption.REPLACE_EXISTING);
}
} catch (IOException ex) {
ex.printStackTrace();
}
Happy Coding !! :)

Can't delete file after being renamed (file is opened)

I am using icefaces to upload files to relative path in my web app (mywebapp/audio), then after the file is getting uploaded I rename it to save its extension as follows:
public static File changeExtToWav(FileInfo fileInfo,
StringBuffer originalFileName) {
log.debug("changeExtToWav");
int mid = fileInfo.getFile().getName().lastIndexOf(".");
String fileName = fileInfo.getFile().getName().substring(0, mid);
originalFileName.append(fileName);
log.debug("originalFileName: " + originalFileName);
String newFileName = fileName + "_" + new Date().getTime() + "."
+ "wav";
File newFile = new File(fileInfo.getFile().getParent() + "/"
+ newFileName);
log.debug("newFileName: " + newFile.getName());
fileInfo.getFile().renameTo(newFile);
return newFile;
}
after the file is getting uploaded, sometimes I want to delete it from UI button as follows:
try {
File fileToDelete = new File(filePath); // correct file path
log.debug("file exists: " + fileToDelete.exists()); // true
fileToDelete.delete();
} catch (Exception e) {
e.printStackTrace();
}
the file path is correct, and I get no exceptions, but the file is not deleted (I am using java 6 btw).
please advise how to fix this issue.
UPDATE: using the following useful method, I can get that the file is opened, any ideas how to close it ?
public String getReasonForFileDeletionFailureInPlainEnglish(File file) {
try {
if (!file.exists())
return "It doesn't exist in the first place.";
else if (file.isDirectory() && file.list().length > 0)
return "It's a directory and it's not empty.";
else
return "Somebody else has it open, we don't have write permissions, or somebody stole my disk.";
} catch (SecurityException e) {
return "We're sandboxed and don't have filesystem access.";
}
}

Well if the file is open, then there is two solutions :
You have a stream in your program open on this file. Note that afaik it's a problem on Windows, with Unix I can delete a File even if a stream is opened on it.
You have an other process using this file. So in this case you can't do anything from Java.
In the log it tells also that it can be a permission problem, are you sure you have enough privileges?
You can also use Files#delete(Path path) (jdk7) to have more details about the issue.

How to create multiple directories given the folder names

I have a list of files, the names of these files are are made of a classgroup and an id (eg. science_000000001.java)
i am able to get the names of all the files and split them so i am putting the classgroups into one array and the ids in another.. i have it so that the arrays cant have two of the same values.
This is the problem, i want to create a directory with these classgroups and ids, an example:
science_000000001.java would be in science/000000001/science_000000001.java
science_000000002.java would be in science/000000002/science_000000002.java
maths_000000001.java would be in maths/000000001/maths_000000001.java
but i cannot think of a way to loop through the arrays correctly to create the appropriate directories?
Also i am able to create the folders myself, its just getting the correct directories is the problem, does anyone have any ideas?

Given:
String filename = "science_000000001.java";
Then
File fullPathFile = new File(filename.replaceAll("(\\w+)_(\\d+).*", "$1/$2/$0"));
gives you the full path of the file, in this case science/000000001/science_000000001.java
If you want to create the directory, use this:
fullPathFile.getParentFile().mkdirs();

The above answer is really good for creating new files with that naming convention. If you wanted to sort existing files into their relative classgroups and Ids you could use the following code:
public static void main(String[] args) {
String dirPath = "D:\\temp\\";
File dir = new File(dirPath);
// Get Directory Listing
File[] fileList = dir.listFiles();
// Process each file
for(int i=0; i < fileList.length; i++)
{
if(fileList[i].isFile()) {
String fileName = fileList[i].getName();
// Split at the file extension and the classgroup
String[] fileParts = fileName.split("[_\\.]");
System.out.println("One: " + fileParts[0] + ", Two: " + fileParts[1]);
// Check directory exists
File newDir = new File(dirPath + fileParts[0] + "\\" + fileParts[1]);
if(!newDir.exists()) {
// Create directory
if(newDir.mkdirs()) {
System.out.println("Directory Created");
}
}
// Move file into directory
if(fileList[i].renameTo(new File(dirPath + fileParts[0] + "\\" + fileParts[1] + "\\" + fileName))) {
System.out.println("File Moved");
}
}
}
}
Hope that helps.

Why am I having nondeterministic file deletion errors when using DiskFileItem?

My upload servlet keeps throwing me an exception saying that the file that I'm trying to replace (near the end of my code) could not be deleted at (seemingly) random. I don't know what's causing this since I'm not using any streams and the file isn't open in my browser. Does anyone know what could be causing this? I'm completely clueless on this one as the code seems correct to me. This is the first time I've used DiskFileItem so I'm not sure if there are any nuances to handle there.
Keep in mind that it sometimes works, sometimes doesn't. I'm lost on that.
Problem Area:
File destination = new File(wellnessDir + File.separator + fileName + ".pdf");
System.out.println("destination file exists: " + destination.exists());
System.out.println("file to be moved exists: " + uploadedFile.exists());
if(destination.exists()){
boolean deleted = destination.delete();
if(!deleted)
throw new Exception("Could not delete file at " + destination);
}
My System outs always say that both file and destination exist. I'm trying to get the upload to overwrite the existing file.
Full code: (& pastebin)
private void uploadRequestHandler(ServletFileUpload upload, HttpServletRequest request)
{
// Handle the request
String fileName = "blank";
try{
List items = upload.parseRequest(request);
//Process the uploaded items
Iterator iter = items.iterator();
File uploadedFile = new File(getHome() + File.separator + "temp");
if(uploadedFile.exists()){
boolean tempDeleted = uploadedFile.delete();
if(!tempDeleted)
throw new Exception("Existing temp file could not be deleted.");
}
//write the file
while (iter.hasNext()) {
DiskFileItem item = (DiskFileItem) iter.next();
if(item.isFormField()){
String fieldName = item.getFieldName();
String fieldValue = item.getString();
if(fieldName.equals("fileName"))
fileName = fieldValue;
//other form values would need to be handled here, right now only need for fileName
}else{
item.write(uploadedFile);
}
}
if(fileName.equals("blank"))
throw new Exception("File name could not be parsed.");
//move file
File wellnessDir = new File(getHome() + File.separator + "medcottage" + File.separator + "wellness");
File destination = new File(wellnessDir + File.separator + fileName + ".pdf");
System.out.println("destination file exists: " + destination.exists());
System.out.println("file to be moved exists: " + uploadedFile.exists());
if(destination.exists()){
boolean deleted = destination.delete();
if(!deleted)
throw new Exception("Could not delete file at " + destination);
}
FileUtil.move(uploadedFile, new File(wellnessDir + File.separator + fileName + ".pdf"));
writeResponse();
} catch (Exception e) {
System.out.println("Error handling upload request.");
e.printStackTrace();
}
}
edit: to add, getHome() and "home" aren't really in the code, that's just to protect my home path

After much testing and aggravation, finally tried it on a different machine, same code, worked great. Has something to do with me transferring domains on my work machine and it messing with permissions.